diff --git a/application/basilisk/app/profile/basilisk.js b/application/basilisk/app/profile/basilisk.js
index 3ad2babe4b..773f6b56c0 100644
--- a/application/basilisk/app/profile/basilisk.js
+++ b/application/basilisk/app/profile/basilisk.js
@@ -1006,12 +1006,7 @@ pref("services.sync.syncedTabs.showRemoteIcons", true);
 
 pref("services.sync.sendTabToDevice.enabled", true);
 
-// Developer edition preferences
-#ifdef MOZ_DEV_EDITION
-sticky_pref("lightweightThemes.selectedThemeID", "firefox-devedition@mozilla.org");
-#else
 sticky_pref("lightweightThemes.selectedThemeID", "");
-#endif
 
 // Whether the character encoding menu is under the main Firefox button. This
 // preference is a string so that localizers can alter it.
diff --git a/application/basilisk/base/content/browser-devedition.js b/application/basilisk/base/content/browser-devedition.js
deleted file mode 100644
index 0dc1e94da5..0000000000
--- a/application/basilisk/base/content/browser-devedition.js
+++ /dev/null
@@ -1,142 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/**
- * Listeners for the DevEdition theme.  This adds an extra stylesheet
- * to browser.xul if a pref is set and no other themes are applied.
- */
-var DevEdition = {
-  _devtoolsThemePrefName: "devtools.theme",
-  styleSheetLocation: "chrome://browser/skin/devedition.css",
-  styleSheet: null,
-  initialized: false,
-
-  get isStyleSheetEnabled() {
-    return this.styleSheet && !this.styleSheet.sheet.disabled;
-  },
-
-  get isThemeCurrentlyApplied() {
-    let theme = LightweightThemeManager.currentTheme;
-    return theme && theme.id == "firefox-devedition@mozilla.org";
-  },
-
-  init: function () {
-    this.initialized = true;
-    Services.prefs.addObserver(this._devtoolsThemePrefName, this, false);
-    Services.obs.addObserver(this, "lightweight-theme-styling-update", false);
-    Services.obs.addObserver(this, "lightweight-theme-window-updated", false);
-    this._updateDevtoolsThemeAttribute();
-
-    if (this.isThemeCurrentlyApplied) {
-      this._toggleStyleSheet(true);
-    }
-  },
-
-  createStyleSheet: function() {
-    let styleSheetAttr = `href="${this.styleSheetLocation}" type="text/css"`;
-    this.styleSheet = document.createProcessingInstruction(
-      "xml-stylesheet", styleSheetAttr);
-    this.styleSheet.addEventListener("load", this);
-    document.insertBefore(this.styleSheet, document.documentElement);
-    this.styleSheet.sheet.disabled = true;
-  },
-
-  observe: function (subject, topic, data) {
-    if (topic == "lightweight-theme-styling-update") {
-      let newTheme = JSON.parse(data);
-      if (newTheme && newTheme.id == "firefox-devedition@mozilla.org") {
-        this._toggleStyleSheet(true);
-      } else {
-        this._toggleStyleSheet(false);
-      }
-    } else if (topic == "lightweight-theme-window-updated" && subject == window) {
-      this._updateLWTBrightness();
-    }
-
-    if (topic == "nsPref:changed" && data == this._devtoolsThemePrefName) {
-      this._updateDevtoolsThemeAttribute();
-    }
-  },
-
-  _inferBrightness: function() {
-    ToolbarIconColor.inferFromText();
-    // Get an inverted full screen button if the dark theme is applied.
-    if (this.isStyleSheetEnabled &&
-        document.documentElement.getAttribute("devtoolstheme") == "dark") {
-      document.documentElement.setAttribute("brighttitlebarforeground", "true");
-    } else {
-      document.documentElement.removeAttribute("brighttitlebarforeground");
-    }
-  },
-
-  _updateLWTBrightness() {
-    if (this.isThemeCurrentlyApplied) {
-      let devtoolsTheme = Services.prefs.getCharPref(this._devtoolsThemePrefName);
-      let textColor = devtoolsTheme == "dark" ? "bright" : "dark";
-      document.documentElement.setAttribute("lwthemetextcolor", textColor);
-    }
-  },
-
-  _updateDevtoolsThemeAttribute: function() {
-    // Set an attribute on root element to make it possible
-    // to change colors based on the selected devtools theme.
-    let devtoolsTheme = Services.prefs.getCharPref(this._devtoolsThemePrefName);
-    if (devtoolsTheme != "dark") {
-      devtoolsTheme = "light";
-    }
-    document.documentElement.setAttribute("devtoolstheme", devtoolsTheme);
-    this._updateLWTBrightness();
-    this._inferBrightness();
-  },
-
-  handleEvent: function(e) {
-    if (e.type === "load") {
-      this.styleSheet.removeEventListener("load", this);
-      this.refreshBrowserDisplay();
-    }
-  },
-
-  refreshBrowserDisplay: function() {
-    // Don't touch things on the browser if gBrowserInit.onLoad hasn't
-    // yet fired.
-    if (this.initialized) {
-      gBrowser.tabContainer._positionPinnedTabs();
-      this._inferBrightness();
-    }
-  },
-
-  _toggleStyleSheet: function(deveditionThemeEnabled) {
-    let wasEnabled = this.isStyleSheetEnabled;
-    if (deveditionThemeEnabled && !wasEnabled) {
-      // The stylesheet may not have been created yet if it wasn't
-      // needed on initial load.  Make it now.
-      if (!this.styleSheet) {
-        this.createStyleSheet();
-      }
-      this.styleSheet.sheet.disabled = false;
-      this.refreshBrowserDisplay();
-    } else if (!deveditionThemeEnabled && wasEnabled) {
-      this.styleSheet.sheet.disabled = true;
-      this.refreshBrowserDisplay();
-    }
-  },
-
-  uninit: function () {
-    Services.prefs.removeObserver(this._devtoolsThemePrefName, this);
-    Services.obs.removeObserver(this, "lightweight-theme-styling-update", false);
-    Services.obs.removeObserver(this, "lightweight-theme-window-updated", false);
-    if (this.styleSheet) {
-      this.styleSheet.removeEventListener("load", this);
-    }
-    this.styleSheet = null;
-  }
-};
-
-// If the DevEdition theme is going to be applied in gBrowserInit.onLoad,
-// then preload it now.  This prevents a flash of unstyled content where the
-// normal theme is applied while the DevEdition stylesheet is loading.
-if (!AppConstants.RELEASE_OR_BETA &&
-    this != Services.appShell.hiddenDOMWindow && DevEdition.isThemeCurrentlyApplied) {
-  DevEdition.createStyleSheet();
-}
diff --git a/application/basilisk/base/content/browser.js b/application/basilisk/base/content/browser.js
index c41899d6f9..2810f467c3 100644
--- a/application/basilisk/base/content/browser.js
+++ b/application/basilisk/base/content/browser.js
@@ -984,7 +984,6 @@ var gBrowserInit = {
     gPageStyleMenu.init();
     BrowserOnClick.init();
     FeedHandler.init();
-    DevEdition.init();
     AboutPrivateBrowsingListener.init();
     TrackingProtection.init();
     RefreshBlocker.init();
@@ -1517,8 +1516,6 @@ var gBrowserInit = {
 
     FeedHandler.uninit();
 
-    DevEdition.uninit();
-
     TrackingProtection.uninit();
 
     RefreshBlocker.uninit();
diff --git a/application/basilisk/base/content/global-scripts.inc b/application/basilisk/base/content/global-scripts.inc
index db8496cfce..6edb112140 100644
--- a/application/basilisk/base/content/global-scripts.inc
+++ b/application/basilisk/base/content/global-scripts.inc
@@ -14,7 +14,6 @@
 <script type="application/javascript" src="chrome://browser/content/browser-captivePortal.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-ctrlTab.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-customization.js"/>
-<script type="application/javascript" src="chrome://browser/content/browser-devedition.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-feeds.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-fullScreenAndPointerLock.js"/>
 <script type="application/javascript" src="chrome://browser/content/browser-fullZoom.js"/>
diff --git a/application/basilisk/base/jar.mn b/application/basilisk/base/jar.mn
index a4b90f90ce..f2b82ba1ee 100644
--- a/application/basilisk/base/jar.mn
+++ b/application/basilisk/base/jar.mn
@@ -66,7 +66,6 @@ browser.jar:
         content/browser/browser-ctrlTab.js            (content/browser-ctrlTab.js)
         content/browser/browser-customization.js      (content/browser-customization.js)
         content/browser/browser-data-submission-info-bar.js (content/browser-data-submission-info-bar.js)
-        content/browser/browser-devedition.js         (content/browser-devedition.js)
         content/browser/browser-feeds.js              (content/browser-feeds.js)
         content/browser/browser-fullScreenAndPointerLock.js  (content/browser-fullScreenAndPointerLock.js)
         content/browser/browser-fullZoom.js           (content/browser-fullZoom.js)
diff --git a/application/basilisk/components/customizableui/CustomizableUI.jsm b/application/basilisk/components/customizableui/CustomizableUI.jsm
index 8302dec1ae..cb92639619 100644
--- a/application/basilisk/components/customizableui/CustomizableUI.jsm
+++ b/application/basilisk/components/customizableui/CustomizableUI.jsm
@@ -198,9 +198,7 @@ var CustomizableUIInternal = {
       "add-ons-button",
     ];
 
-    if (!AppConstants.MOZ_DEV_EDITION) {
-      panelPlacements.splice(-1, 0, "developer-button");
-    }
+    panelPlacements.splice(-1, 0, "developer-button");
 
     let showCharacterEncoding = Services.prefs.getComplexValue(
       "browser.menu.showCharacterEncoding",
@@ -225,10 +223,6 @@ var CustomizableUIInternal = {
       "home-button",
     ];
 
-    if (AppConstants.MOZ_DEV_EDITION) {
-      navbarPlacements.splice(2, 0, "developer-button");
-    }
-
     // Place this last, when createWidget is called for pocket, it will
     // append to the toolbar.
     if (Services.prefs.getPrefType("extensions.pocket.enabled") != Services.prefs.PREF_INVALID &&
diff --git a/application/basilisk/components/nsBrowserGlue.js b/application/basilisk/components/nsBrowserGlue.js
index ad0b7ed7fb..5d3e4689bb 100644
--- a/application/basilisk/components/nsBrowserGlue.js
+++ b/application/basilisk/components/nsBrowserGlue.js
@@ -676,19 +676,6 @@ BrowserGlue.prototype = {
     // Ensure we keep track of places/pw-mananager undo by init'ing this early.
     Cu.import("resource:///modules/AutoMigrate.jsm");
 
-    if (!AppConstants.RELEASE_OR_BETA) {
-      let themeName = gBrowserBundle.GetStringFromName("deveditionTheme.name");
-      let vendorShortName = gBrandBundle.GetStringFromName("vendorShortName");
-
-      LightweightThemeManager.addBuiltInTheme({
-        id: "firefox-devedition@mozilla.org",
-        name: themeName,
-        headerURL: "resource:///chrome/browser/content/browser/defaultthemes/devedition.header.png",
-        iconURL: "resource:///chrome/browser/content/browser/defaultthemes/devedition.icon.png",
-        author: vendorShortName,
-      });
-    }
-
     TabCrashHandler.init();
 
     Services.obs.notifyObservers(null, "browser-ui-startup-complete", "");
@@ -1054,10 +1041,6 @@ BrowserGlue.prototype = {
 
   // All initial windows have opened.
   _onWindowsRestored: function BG__onWindowsRestored() {
-    if (AppConstants.MOZ_DEV_EDITION) {
-      this._createExtraDefaultProfile();
-    }
-
     this._initServiceDiscovery();
 
     // Show update notification, if needed.
@@ -1193,40 +1176,6 @@ BrowserGlue.prototype = {
     E10SAccessibilityCheck.onWindowsRestored();
   },
 
-  _createExtraDefaultProfile: function () {
-    if (!AppConstants.MOZ_DEV_EDITION) {
-      return;
-    }
-    // If Developer Edition is the only installed Firefox version and no other
-    // profiles are present, create a second one for use by other versions.
-    // This helps Firefox versions earlier than 35 avoid accidentally using the
-    // unsuitable Developer Edition profile.
-    let profileService = Cc["@mozilla.org/toolkit/profile-service;1"]
-                         .getService(Ci.nsIToolkitProfileService);
-    let profileCount = profileService.profileCount;
-    if (profileCount == 1 && profileService.selectedProfile.name != "default") {
-      let newProfile;
-      try {
-        newProfile = profileService.createProfile(null, "default");
-        profileService.defaultProfile = newProfile;
-        profileService.flush();
-      } catch (e) {
-        Cu.reportError("Could not create profile 'default': " + e);
-      }
-      if (newProfile) {
-        // We don't want a default profile with Developer Edition settings, an
-        // empty profile directory will do. The profile service of the other
-        // Firefox will populate it with its own stuff.
-        let newProfilePath = newProfile.rootDir.path;
-        OS.File.removeDir(newProfilePath).then(() => {
-          return OS.File.makeDir(newProfilePath);
-        }).then(null, e => {
-          Cu.reportError("Could not empty profile 'default': " + e);
-        });
-      }
-    }
-  },
-
   _onQuitRequest: function BG__onQuitRequest(aCancelQuit, aQuitType) {
     // If user has already dismissed quit request, then do nothing
     if ((aCancelQuit instanceof Ci.nsISupportsPRBool) && aCancelQuit.data)
@@ -1981,14 +1930,8 @@ BrowserGlue.prototype = {
          defaultThemeSelected = Services.prefs.getCharPref("general.skins.selectedSkin") == "classic/1.0";
       } catch (e) {}
 
-      // If we are on the devedition channel, the devedition theme is on by
-      // default.  But we need to handle the case where they didn't want it
-      // applied, and unapply the theme.
-      let userChoseToNotUseDeveditionTheme =
-        !defaultThemeSelected ||
-        (lightweightThemeSelected && selectedThemeID != "firefox-devedition@mozilla.org");
-
-      if (userChoseToNotUseDeveditionTheme && selectedThemeID == "firefox-devedition@mozilla.org") {
+      // If we have the dev edition theme selected, reset it.
+      if (selectedThemeID == "firefox-devedition@mozilla.org") {
         Services.prefs.setCharPref("lightweightThemes.selectedThemeID", "");
       }
 
diff --git a/application/basilisk/components/places/content/controller.js b/application/basilisk/components/places/content/controller.js
index ebdab60f4c..931c8fac14 100644
--- a/application/basilisk/components/places/content/controller.js
+++ b/application/basilisk/components/places/content/controller.js
@@ -461,7 +461,11 @@ PlacesController.prototype = {
             if (parentNode) {
               if (PlacesUtils.nodeIsTagQuery(parentNode))
                 nodeData["tagChild"] = true;
-              else if (this.hasCachedLivemarkInfo(parentNode))
+            }
+          } else {
+            var parentNode = node.parent;
+            if (parentNode) {
+              if (this.hasCachedLivemarkInfo(parentNode))
                 nodeData["livemarkChild"] = true;
             }
           }
diff --git a/application/basilisk/components/places/content/placesOverlay.xul b/application/basilisk/components/places/content/placesOverlay.xul
index 512eb923e3..2dbef0f049 100644
--- a/application/basilisk/components/places/content/placesOverlay.xul
+++ b/application/basilisk/components/places/content/placesOverlay.xul
@@ -198,7 +198,7 @@
               accesskey="&cmd.delete.accesskey;"
               closemenu="single"
               selection="link"
-              forcehideselection="bookmark"/>
+              forcehideselection="bookmark|livemarkChild"/>
     <menuitem id="placesContext_deleteHost"
               command="placesCmd_deleteDataHost"
               label="&cmd.deleteDomainData.label;"
@@ -207,7 +207,7 @@
               selection="link|host"
               selectiontype="single"
               hideifprivatebrowsing="true"
-              forcehideselection="bookmark"/>
+              forcehideselection="bookmark|livemarkChild"/>
     <menuseparator id="placesContext_deleteSeparator"/>
     <menuitem id="placesContext_sortBy:name"
               command="placesCmd_sortBy:name"
diff --git a/application/basilisk/components/preferences/in-content/main.js b/application/basilisk/components/preferences/in-content/main.js
index bac771bece..8f3dffa57b 100644
--- a/application/basilisk/components/preferences/in-content/main.js
+++ b/application/basilisk/components/preferences/in-content/main.js
@@ -78,18 +78,6 @@ var gMainPane = {
     setEventListener("chooseFolder", "command",
                      gMainPane.chooseFolder);
 
-    if (AppConstants.MOZ_DEV_EDITION) {
-      let uAppData = OS.Constants.Path.userApplicationDataDir;
-      let ignoreSeparateProfile = OS.Path.join(uAppData, "ignore-dev-edition-profile");
-
-      setEventListener("separateProfileMode", "command", gMainPane.separateProfileModeChange);
-      let separateProfileModeCheckbox = document.getElementById("separateProfileMode");
-      setEventListener("getStarted", "click", gMainPane.onGetStarted);
-
-      OS.File.stat(ignoreSeparateProfile).then(() => separateProfileModeCheckbox.checked = false,
-                                               () => separateProfileModeCheckbox.checked = true);
-    }
-
     // Notify observers that the UI is now ready
     Components.classes["@mozilla.org/observer-service;1"]
               .getService(Components.interfaces.nsIObserverService)
@@ -101,71 +89,6 @@ var gMainPane = {
     // **STUB**
   },
 
-  separateProfileModeChange: function ()
-  {
-    if (AppConstants.MOZ_DEV_EDITION) {
-      function quitApp() {
-        Services.startup.quit(Ci.nsIAppStartup.eAttemptQuit |  Ci.nsIAppStartup.eRestartNotSameProfile);
-      }
-      function revertCheckbox(error) {
-        separateProfileModeCheckbox.checked = !separateProfileModeCheckbox.checked;
-        if (error) {
-          Cu.reportError("Failed to toggle separate profile mode: " + error);
-        }
-      }
-      function createOrRemoveSpecialDevEditionFile(onSuccess) {
-        let uAppData = OS.Constants.Path.userApplicationDataDir;
-        let ignoreSeparateProfile = OS.Path.join(uAppData, "ignore-dev-edition-profile");
-
-        if (separateProfileModeCheckbox.checked) {
-          OS.File.remove(ignoreSeparateProfile).then(onSuccess, revertCheckbox);
-        } else {
-          OS.File.writeAtomic(ignoreSeparateProfile, new Uint8Array()).then(onSuccess, revertCheckbox);
-        }
-      }
-
-      let separateProfileModeCheckbox = document.getElementById("separateProfileMode");
-      let button_index = confirmRestartPrompt(separateProfileModeCheckbox.checked,
-                                              0, false, true);
-      switch (button_index) {
-        case CONFIRM_RESTART_PROMPT_CANCEL:
-          revertCheckbox();
-          return;
-        case CONFIRM_RESTART_PROMPT_RESTART_NOW:
-          const Cc = Components.classes, Ci = Components.interfaces;
-          let cancelQuit = Cc["@mozilla.org/supports-PRBool;1"]
-                             .createInstance(Ci.nsISupportsPRBool);
-          Services.obs.notifyObservers(cancelQuit, "quit-application-requested",
-                                        "restart");
-          if (!cancelQuit.data) {
-            createOrRemoveSpecialDevEditionFile(quitApp);
-            return;
-          }
-
-          // Revert the checkbox in case we didn't quit
-          revertCheckbox();
-          return;
-        case CONFIRM_RESTART_PROMPT_RESTART_LATER:
-          createOrRemoveSpecialDevEditionFile();
-          return;
-      }
-    }
-  },
-
-  onGetStarted: function (aEvent) {
-    if (AppConstants.MOZ_DEV_EDITION) {
-      const Cc = Components.classes, Ci = Components.interfaces;
-      let wm = Cc["@mozilla.org/appshell/window-mediator;1"]
-                  .getService(Ci.nsIWindowMediator);
-      let win = wm.getMostRecentWindow("navigator:browser");
-
-      if (win) {
-        let accountsTab = win.gBrowser.addTab("about:accounts?action=signin&entrypoint=dev-edition-setup");
-        win.gBrowser.selectedTab = accountsTab;
-      }
-    }
-  },
-
   // HOME PAGE
 
   /*
diff --git a/application/basilisk/components/preferences/in-content/main.xul b/application/basilisk/components/preferences/in-content/main.xul
index 8eca118772..f695b308bd 100644
--- a/application/basilisk/components/preferences/in-content/main.xul
+++ b/application/basilisk/components/preferences/in-content/main.xul
@@ -112,17 +112,6 @@
           hidden="true">
   <caption><label>&startup.label;</label></caption>
 
-#ifdef MOZ_DEV_EDITION
-  <vbox id="separateProfileBox">
-    <checkbox id="separateProfileMode"
-              label="&separateProfileMode.label;"/>
-    <hbox align="center" class="indent">
-      <label id="useFirefoxSync">&useFirefoxSync.label;</label>
-      <label id="getStarted" class="text-link">&getStarted.label;</label>
-    </hbox>
-  </vbox>
-#endif
-
 #ifdef HAVE_SHELL_SERVICE
   <vbox id="defaultBrowserBox">
     <hbox align="center">
diff --git a/application/basilisk/modules/ProcessHangMonitor.jsm b/application/basilisk/modules/ProcessHangMonitor.jsm
index b1f6f2a97e..80c506ac75 100644
--- a/application/basilisk/modules/ProcessHangMonitor.jsm
+++ b/application/basilisk/modules/ProcessHangMonitor.jsm
@@ -304,16 +304,6 @@ var ProcessHangMonitor = {
         }
       }];
 
-    if (AppConstants.MOZ_DEV_EDITION && report.hangType == report.SLOW_SCRIPT) {
-      buttons.push({
-        label: bundle.getString("processHang.button_debug.label"),
-        accessKey: bundle.getString("processHang.button_debug.accessKey"),
-        callback: function() {
-          ProcessHangMonitor.debugScript(win);
-        }
-      });
-    }
-
     nb.appendNotification(bundle.getString("processHang.label"),
                           "process-hang",
                           "chrome://browser/skin/slowStartup-16.png",
diff --git a/application/basilisk/themes/linux/devedition.css b/application/basilisk/themes/linux/devedition.css
deleted file mode 100644
index 1f16d5d63b..0000000000
--- a/application/basilisk/themes/linux/devedition.css
+++ /dev/null
@@ -1,106 +0,0 @@
-% This Source Code Form is subject to the terms of the Mozilla Public
-% License, v. 2.0. If a copy of the MPL was not distributed with this
-% file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-%include ../shared/devedition.inc.css
-
-:root {
-  --forwardbutton-width: 29px;
-}
-
-:root[devtoolstheme="light"] {
-  --urlbar-dropmarker-url: url("chrome://browser/skin/devedition/urlbar-history-dropmarker.svg");
-  --urlbar-dropmarker-region: rect(0px, 11px, 14px, 0px);
-  --urlbar-dropmarker-hover-region: rect(0, 22px, 14px, 11px);
-  --urlbar-dropmarker-active-region: rect(0px, 33px, 14px, 22px);
-  --urlbar-dropmarker-2x-url: url("chrome://browser/skin/devedition/urlbar-history-dropmarker.svg");
-  --urlbar-dropmarker-2x-region: rect(0px, 11px, 14px, 0px);
-  --urlbar-dropmarker-hover-2x-region: rect(0, 22px, 14px, 11px);
-  --urlbar-dropmarker-active-2x-region: rect(0px, 33px, 14px, 22px);
-}
-
-:root[devtoolstheme="dark"] .findbar-closebutton:not(:hover),
-:root[devtoolstheme="dark"] #sidebar-header > .close-icon:not(:hover),
-.tab-close-button[selected]:not(:hover) {
-  background-image: -moz-image-rect(url("chrome://global/skin/icons/close.svg"), 0, 80, 16, 64);
-}
-
-/* The menubar and tabs toolbar should match the devedition theme */
-#TabsToolbar,
-#toolbar-menubar {
-  -moz-appearance: none !important;
-}
-#main-menubar {
-  color: var(--chrome-color);
-}
-#main-menubar > menu:not([open]) {
-  color: inherit;
-}
-
-/* Allow buttons with -moz-appearance set to look normal on hover and open states */
-#navigator-toolbox .toolbarbutton-1:-moz-any(:hover, [open="true"]),
-#PlacesToolbar toolbarbutton.bookmark-item:-moz-any(:hover, [open="true"]) {
-  color: initial;
-}
-
-/* Square back and forward buttons */
-#back-button > .toolbarbutton-icon,
-#forward-button > .toolbarbutton-icon {
-  margin: 0;
-  border: 1px solid var(--chrome-nav-bar-controls-border-color);
-  padding: 2px 5px;
-  background: var(--chrome-nav-buttons-background);
-  box-shadow: none !important;
-}
-
-#forward-button > .toolbarbutton-icon {
-  border-inline-start: none;
-}
-
-/* Override a box shadow for disabled back button */
-#main-window:not([customizing]) #back-button[disabled] > .toolbarbutton-icon {
-  box-shadow: none !important;
-}
-
-#back-button:hover:not([disabled="true"]) > .toolbarbutton-icon,
-#forward-button:hover:not([disabled="true"]) > .toolbarbutton-icon {
-  background: var(--chrome-nav-buttons-hover-background) !important;
-}
-
-#back-button > .toolbarbutton-icon {
-  border-radius: 2px 0 0 2px !important;
-}
-
-.urlbar-history-dropmarker {
-  -moz-appearance: none;
-  padding: 0 3px;
-  list-style-image: var(--urlbar-dropmarker-url);
-  -moz-image-region: var(--urlbar-dropmarker-region);
-}
-
-/* Add the proper background for tab overflow */
-#alltabs-button,
-#new-tab-button {
-  background: var(--chrome-background-color);
-}
-
-#new-tab-button:hover > .toolbarbutton-icon {
-  border-color: transparent !important;
-}
-
-/* Prevent double border below tabs toolbar */
-#TabsToolbar:not([collapsed="true"]) + #nav-bar {
-  border-top-width: 0 !important;
-}
-
-/* Fix the bad-looking text-shadow in the sidebar header: */
-.sidebar-header,
-#sidebar-header {
-  text-shadow: none;
-}
-
-.ac-type-icon {
-  /* Left-align the type icon in awesomebar popup results with the icon in the
-     urlbar. */
-  margin-inline-start: 11px;
-}
diff --git a/application/basilisk/themes/linux/jar.mn b/application/basilisk/themes/linux/jar.mn
index e9f666418b..81581dfaa9 100644
--- a/application/basilisk/themes/linux/jar.mn
+++ b/application/basilisk/themes/linux/jar.mn
@@ -13,7 +13,6 @@ browser.jar:
 #endif
   skin/classic/browser/actionicon-tab.png
 * skin/classic/browser/browser.css
-* skin/classic/browser/devedition.css
 * skin/classic/browser/browser-lightweightTheme.css
   skin/classic/browser/click-to-play-warning-stripes.png
   skin/classic/browser/Info.png
diff --git a/application/basilisk/themes/osx/devedition.css b/application/basilisk/themes/osx/devedition.css
deleted file mode 100644
index c7a2bdd714..0000000000
--- a/application/basilisk/themes/osx/devedition.css
+++ /dev/null
@@ -1,121 +0,0 @@
-% This Source Code Form is subject to the terms of the Mozilla Public
-% License, v. 2.0. If a copy of the MPL was not distributed with this
-% file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-%include ../shared/devedition.inc.css
-
-:root {
-  --forwardbutton-width: 32px;
-}
-
-/* Use only 1px separator between nav toolbox and page content */
-#navigator-toolbox::after {
-  border-top-style: none;
-  margin-top: -1px;
-}
-
-/* Include extra space on left/right for dragging since there is no space above
-   the tabs */
-#main-window[tabsintitlebar] #TabsToolbar {
-  padding-left: 50px;
-  padding-right: 50px;
-  margin-bottom: 0; /* Don't overlap the inner highlight at the top of the nav-bar */
-}
-
-/* Get rid of 1px bright strip at the top of window */
-#main-window[tabsintitlebar] #titlebar-content {
-  background: var(--chrome-background-color);
-}
-
-/* Resize things so that the native titlebar is in line with the tabs */
-#main-window[tabsintitlebar] > #titlebar > #titlebar-content > #titlebar-buttonbox-container,
-#main-window[tabsintitlebar] > #titlebar > #titlebar-content > #titlebar-secondary-buttonbox > #titlebar-fullscreen-button {
-  margin-top: 6px;
-}
-
-/* Square back and forward buttons.  Need !important on these because there
-   are a lot of more specific selectors sprinkled around elsewhere for changing
-   background / shadows for different states */
-#back-button,
-#forward-button {
-  height: 24px !important;
-  box-shadow: none !important;
-  border: 1px solid var(--chrome-nav-bar-controls-border-color) !important;
-  background: var(--chrome-nav-buttons-background) !important;
-}
-
-#forward-button {
-  border-inline-start: none !important;
-  /* browser.css and friends set up the width of the button to be 32px.
-   * They then set margin-left to -2px to ensure the button is not too wide
-   * compared to the back button, and set padding-left to center the icon
-   * correctly.
-   * In our theme, the back and forward buttons are the same width, with the
-   * back button being 32px with 1px border on both sides. To ensure the
-   * forward button's content box looks like it is the same size with width
-   * set to 32px and a 1px border on only 1 side, we overlap by 1px, so both
-   * buttons end up with a content box that looks like it's 30px.
-   */
-  margin-left: -1px;
-  padding-left: 1px;
-}
-
-#forward-button > .toolbarbutton-icon {
-  margin-left: 0;
-  margin-right: 0;
-}
-
-#back-button:hover:not([disabled="true"]),
-#forward-button:hover:not([disabled="true"]) {
-  background: var(--chrome-nav-buttons-hover-background) !important;
-}
-
-#back-button {
-  border-radius: 3px 0 0 3px !important;
-  padding: 0 !important;
-  margin: 0 !important;
-}
-
-#back-button:hover:active:not([disabled="true"]) {
-  -moz-image-region: rect(18px, 54px, 36px, 36px);
-}
-
-/* Use smaller back button icon */
-@media (min-resolution: 2dppx) {
-  #back-button:hover:active:not([disabled="true"]) {
-    -moz-image-region: rect(36px, 108px, 72px, 72px);
-  }
-}
-
-/* Don't use the default background for tabs toolbar */
-#TabsToolbar {
-  -moz-appearance: none !important;
-}
-
-/* Prevent the hover styling from on the identity icon from overlapping the
-   urlbar border. */
-#identity-box {
-  margin-top: -1px !important;
-  margin-bottom: -1px !important;
-  padding-top: 3px !important;
-  padding-bottom: 3px !important;
-}
-
-:root[devtoolstheme="dark"] .findbar-closebutton:not(:hover),
-/* Tab styling - make sure to use an inverted icon for the selected tab
-   (brighttext only covers the unselected tabs) */
-.tab-close-button[selected=true]:not(:hover) {
-  -moz-image-region: rect(0, 64px, 16px, 48px);
-}
-@media (min-resolution: 2dppx) {
-  :root[devtoolstheme="dark"] .findbar-closebutton:not(:hover),
-  .tab-close-button[selected=true]:not(:hover) {
-    -moz-image-region: rect(0, 128px, 32px, 96px);
-  }
-}
-
-.ac-type-icon {
-  /* Left-align the type icon in awesomebar popup results with the icon in the
-     urlbar. */
-  margin-inline-start: 14px;
-}
diff --git a/application/basilisk/themes/osx/jar.mn b/application/basilisk/themes/osx/jar.mn
index 92d2ceedf5..5dec6559ad 100644
--- a/application/basilisk/themes/osx/jar.mn
+++ b/application/basilisk/themes/osx/jar.mn
@@ -13,7 +13,6 @@ browser.jar:
   skin/classic/browser/actionicon-tab.png
   skin/classic/browser/actionicon-tab@2x.png
 * skin/classic/browser/browser.css
-* skin/classic/browser/devedition.css
 * skin/classic/browser/browser-lightweightTheme.css
   skin/classic/browser/click-to-play-warning-stripes.png
   skin/classic/browser/Info.png
diff --git a/application/basilisk/themes/shared/devedition.inc.css b/application/basilisk/themes/shared/devedition.inc.css
deleted file mode 100644
index a5c0db9489..0000000000
--- a/application/basilisk/themes/shared/devedition.inc.css
+++ /dev/null
@@ -1,311 +0,0 @@
-% This Source Code Form is subject to the terms of the Mozilla Public
-% License, v. 2.0. If a copy of the MPL was not distributed with this
-% file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-/* devedition.css is loaded in browser.xul after browser.css when it is
-   preffed on.  The bulk of the styling is here in the shared file, but
-   there are overrides for each platform in their devedition.css files. */
-
-:root {
-  --tab-toolbar-navbar-overlap: 0px;
-  --navbar-tab-toolbar-highlight-overlap: 0px;
-  --space-above-tabbar: 0px;
-  --toolbarbutton-text-shadow: none;
-  --backbutton-urlbar-overlap: 0px;
-}
-
-:root[devtoolstheme="dark"] {
-  /* Chrome */
-  --chrome-background-color: #272b35;
-  --chrome-color: #F5F7FA;
-  --chrome-secondary-background-color: #393F4C;
-  --chrome-navigator-toolbox-separator-color: rgba(0,0,0,.2);
-  --chrome-nav-bar-separator-color: rgba(0,0,0,.2);
-  --chrome-nav-buttons-background: #252C33;
-  --chrome-nav-buttons-hover-background: #1B2127;
-  --chrome-nav-bar-controls-border-color: #1D2328;
-  --chrome-selection-color: #fff;
-  --chrome-selection-background-color: #5675B9;
-
-  /* Tabs */
-  --tabs-toolbar-color: #F5F7FA;
-  --tab-background-color: #272b35;
-  --tab-hover-background-color: #07090a;
-  --tab-selection-color: #f5f7fa;
-  --tab-selection-background-color: #5675B9;
-  --tab-selection-box-shadow: none;
-  --pinned-tab-glow: radial-gradient(22px at center calc(100% - 2px), rgba(76,158,217,0.9) 13%, rgba(0,0,0,0.4) 16%, transparent 70%);
-
-  /* Url and search bars */
-  --url-and-searchbar-background-color: #171B1F;
-  --urlbar-separator-color: #5F6670;
-  --urlbar-dropmarker-url: url("chrome://browser/skin/devedition/urlbar-history-dropmarker.svg");
-  --urlbar-dropmarker-region: rect(0px, 11px, 14px, 0px);
-  --urlbar-dropmarker-hover-region: rect(0, 22px, 14px, 11px);
-  --urlbar-dropmarker-active-region: rect(0px, 33px, 14px, 22px);
-  --urlbar-dropmarker-2x-url: url("chrome://browser/skin/devedition/urlbar-history-dropmarker.svg");
-  --urlbar-dropmarker-2x-region: rect(0px, 11px, 14px, 0px);
-  --urlbar-dropmarker-hover-2x-region: rect(0, 22px, 14px, 11px);
-  --urlbar-dropmarker-active-2x-region: rect(0px, 33px, 14px, 22px);
-}
-
-/* Override the lwtheme-specific styling for toolbar buttons */
-:root[devtoolstheme="dark"],
-:root[devtoolstheme="dark"] toolbar:-moz-lwtheme {
-  --toolbarbutton-hover-background: rgba(25,33, 38,.6) linear-gradient(rgba(25,33,38,.6), rgba(25,33,38,.6)) padding-box;
-  --toolbarbutton-hover-boxshadow: none;
-  --toolbarbutton-hover-bordercolor: rgba(25,33,38,.6);
-  --toolbarbutton-active-background: rgba(25,33,38,1) linear-gradient(rgba(25,33,38,1), rgba(25,33,38,1)) border-box;
-  --toolbarbutton-active-boxshadow: none;
-  --toolbarbutton-active-bordercolor: rgba(25,33,38,.8);
-  --toolbarbutton-checkedhover-backgroundcolor: #3C5283;
-
-}
-
-:root[devtoolstheme="light"] {
-  --url-and-searchbar-background-color: #fff;
-
-  --chrome-background-color: #E3E4E6;
-  --chrome-color: #18191a;
-  --chrome-secondary-background-color: #f5f6f7;
-  --chrome-navigator-toolbox-separator-color: #cccccc;
-  --chrome-nav-bar-separator-color: #B6B6B8;
-  --chrome-nav-buttons-background: #ffffff; /* --theme-body-background */
-  --chrome-nav-buttons-hover-background: #DADBDB;
-  --chrome-nav-bar-controls-border-color: #ccc;
-  --chrome-selection-color: #f5f7fa;
-  --chrome-selection-background-color: #4c9ed9;
-
-  --tab-background-color: #E3E4E6;
-  --tab-hover-background-color: #D7D8DA;
-  --tab-selection-color: #f5f7fa;
-  --tab-selection-background-color: #4c9ed9;
-  --tab-selection-box-shadow: none;
-  --pinned-tab-glow: radial-gradient(22px at center calc(100% - 2px), rgba(76,158,217,0.9) 13%, transparent 16%);
-}
-
-/* Override the lwtheme-specific styling for toolbar buttons */
-:root[devtoolstheme="light"],
-:root[devtoolstheme="light"] toolbar:-moz-lwtheme {
-  --toolbarbutton-hover-background: #eaeaea;
-  --toolbarbutton-hover-boxshadow: none;
-  --toolbarbutton-hover-bordercolor: rgba(0,0,0,0.1);
-  --toolbarbutton-active-background: #d7d7d8 border-box;
-  --toolbarbutton-active-boxshadow: none;
-  --toolbarbutton-active-bordercolor: rgba(0,0,0,0.15);
-  --toolbarbutton-checkedhover-backgroundcolor: #d7d7d8;
-}
-
-/* Give some space to drag the window around while customizing
-   (normal space to left and right of tabs doesn't work in this case) */
-#main-window[tabsintitlebar][customizing] {
-  --space-above-tabbar: 9px;
-}
-
-/* Override @tabCurveHalfWidth@ and @tabCurveWidth@.  XXX: Switch to a CSS variable once the perf is sorted out - bug 1088771 */
-.tab-background-middle {
-  border-left-width: 0;
-  border-right-width: 0;
-  margin: 0;
-}
-
-.tab-background,
-.tabs-newtab-button {
-  margin-inline-end: 0;
-  margin-inline-start: 0;
-}
-
-.tabbrowser-arrowscrollbox > .arrowscrollbox-scrollbox {
-  padding-inline-end: 0;
-  padding-inline-start: 0;
-}
-
-.tab-background-start[selected=true]::after,
-.tab-background-start[selected=true]::before,
-.tab-background-start,
-.tab-background-end,
-.tab-background-end[selected=true]::after,
-.tab-background-end[selected=true]::before {
-  width: 0;
-}
-
-.tab-background-start[selected=true]::after,
-.tab-background-end[selected=true]::after {
-  margin-inline-start: 0;
-}
-/* End override @tabCurveHalfWidth@ and @tabCurveWidth@ */
-
-#urlbar ::-moz-selection,
-#navigator-toolbox .searchbar-textbox ::-moz-selection,
-.browserContainer > findbar ::-moz-selection {
-  background-color: var(--chrome-selection-background-color);
-  color: var(--chrome-selection-color);
-}
-
-/* Change the base colors for the browser chrome */
-
-#tabbrowser-tabs,
-#TabsToolbar,
-#browser-panel {
-  background: var(--chrome-background-color);
-  color: var(--chrome-color);
-}
-
-#navigator-toolbox:-moz-lwtheme::after {
-  border-bottom-color: var(--chrome-navigator-toolbox-separator-color);
-}
-
-#navigator-toolbox > toolbar:not(#TabsToolbar):not(#toolbar-menubar),
-.browserContainer > findbar,
-#browser-bottombox {
-  background-color: var(--chrome-secondary-background-color) !important;
-  background-image: none !important;
-  color: var(--chrome-color);
-}
-
-/* Default findbar text color doesn't look good - Bug 1125677 */
-.browserContainer > findbar .findbar-find-status,
-.browserContainer > findbar .found-matches {
-  color: inherit;
-}
-
-#navigator-toolbox .toolbarbutton-1,
-.browserContainer > findbar .findbar-button,
-#PlacesToolbar toolbarbutton.bookmark-item {
-  color: var(--chrome-color);
-  text-shadow: var(--toolbarbutton-text-shadow);
-}
-
-/* Using toolbar[brighttext] instead of important to override linux */
-toolbar[brighttext] #downloads-indicator-counter {
-  text-shadow: var(--toolbarbutton-text-shadow);
-  color: var(--chrome-color);
-}
-
-#TabsToolbar {
-  text-shadow: none !important;
-}
-
-/* URL bar and search bar*/
-#urlbar,
-#navigator-toolbox .searchbar-textbox {
-  background-color: var(--url-and-searchbar-background-color) !important;
-  background-image: none !important;
-  color: inherit !important;
-  border: 1px solid var(--chrome-nav-bar-controls-border-color) !important;
-  box-shadow: none !important;
-}
-
-%filter substitution
-%define selectorPrefix :root[devtoolstheme="dark"] 
-%define selectorSuffix :-moz-lwtheme
-%define iconVariant -white
-%include identity-block/icons.inc.css
-
-#urlbar {
-  border-inline-start: none !important;
-  opacity: 1 !important;
-}
-
-window:not([chromehidden~="toolbar"]) #urlbar-wrapper {
-  overflow: -moz-hidden-unscrollable;
-  clip-path: none;
-  margin-inline-start: 0;
-}
-
-:root[devtoolstheme="dark"] #urlbar-zoom-button:hover {
-  background-color: rgba(255,255,255,.2);
-}
-
-:root[devtoolstheme="dark"] #urlbar-zoom-button:hover:active {
-  background-color: rgba(255,255,255,.3);
-}
-
-/* Nav bar specific stuff */
-#nav-bar {
-  margin-top: 0 !important;
-  border-top: none !important;
-  border-bottom: none !important;
-  border-radius: 0 !important;
-  box-shadow: 0 -1px var(--chrome-nav-bar-separator-color) !important;
-}
-
-/* No extra vertical padding for nav bar */
-#nav-bar-customization-target,
-#nav-bar {
-  padding-top: 0;
-  padding-bottom: 0;
-}
-
-/* Use smaller back button icon */
-#back-button {
-  -moz-image-region: rect(0, 54px, 18px, 36px);
-}
-
-@media (min-resolution: 1.1dppx) {
-  #back-button {
-    -moz-image-region: rect(0, 108px, 36px, 72px);
-  }
-}
-
-.tab-background {
-  visibility: hidden;
-}
-
-/* Tab separators */
-.tabbrowser-tab::after,
-.tabbrowser-tab::before {
-  background: currentColor;
-  opacity: 0.2 !important;
-}
-
-.tabbrowser-arrowscrollbox > .scrollbutton-down,
-.tabbrowser-arrowscrollbox > .scrollbutton-up {
-  background-color: var(--tab-background-color);
-  border-color: transparent;
-}
-
-.tabbrowser-tab {
-  /* We normally rely on other tab elements for pointer events, but this
-     theme hides those so we need it set here instead */
-  pointer-events: auto;
-}
-
-.tabbrowser-tab:-moz-any([image], [pinned]) > .tab-stack > .tab-content[attention]:not([selected="true"]),
-.tabbrowser-tab > .tab-stack > .tab-content[pinned][titlechanged]:not([selected="true"]) {
-  background-image: var(--pinned-tab-glow);
-  background-position: center;
-  background-size: 100%;
-}
-
-.tabbrowser-tab[image] > .tab-stack > .tab-content[attention]:not([pinned]):not([selected="true"]) {
-  background-position: left bottom var(--tab-toolbar-navbar-overlap);
-  background-size: 34px 100%;
-}
-
-.tabbrowser-arrowscrollbox > .scrollbutton-down:not([disabled]):hover,
-.tabbrowser-arrowscrollbox > .scrollbutton-up:not([disabled]):hover,
-.tabbrowser-tab:hover {
-  background-color: var(--tab-hover-background-color);
-}
-
-.tabbrowser-tab[visuallyselected] {
-  color: var(--tab-selection-color) !important; /* Override color: inherit */
-  background-color: var(--tab-selection-background-color);
-}
-
-.tab-icon-sound[soundplaying],
-.tab-icon-sound[muted] {
-  filter: url(chrome://browser/skin/filters.svg#fill) !important; /* removes drop-shadow filter */
-}
-
-/* Don't need space for the tab curves (66px - 30px) */
-.tabs-newtab-button {
-  width: 36px;
-}
-
-.tabs-newtab-button:hover {
-  /* Important needed because !important is used in browser.css */
-  background-color: var(--tab-hover-background-color) !important;
-  background-image: none;
-}
diff --git a/application/basilisk/themes/shared/devedition/urlbar-history-dropmarker.svg b/application/basilisk/themes/shared/devedition/urlbar-history-dropmarker.svg
deleted file mode 100644
index 115fbf127e..0000000000
--- a/application/basilisk/themes/shared/devedition/urlbar-history-dropmarker.svg
+++ /dev/null
@@ -1,22 +0,0 @@
-<!-- This Source Code Form is subject to the terms of the Mozilla Public
-   - License, v. 2.0. If a copy of the MPL was not distributed with this
-   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
-<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="33" height="14" viewBox="0 0 33 14">
-  <defs>
-    <polygon points="0,0 5.5,7 11,0" id="dropmarker-shape"/>
-  </defs>
-  <style>
-    use {
-      fill: #b6babf;
-    }
-    .hover {
-      fill: #61bdeb;
-    }
-    .active {
-      fill: #39ace6;
-    }
-  </style>
-  <use xlink:href="#dropmarker-shape" style="transform: translate(0, 4px)"/>
-  <use xlink:href="#dropmarker-shape" style="transform: translate(11px, 4px)" class="hover"/>
-  <use xlink:href="#dropmarker-shape" style="transform: translate(22px, 4px)" class="active"/>
-</svg>
diff --git a/application/basilisk/themes/shared/jar.inc.mn b/application/basilisk/themes/shared/jar.inc.mn
index 361edd3117..1fc7769a5d 100644
--- a/application/basilisk/themes/shared/jar.inc.mn
+++ b/application/basilisk/themes/shared/jar.inc.mn
@@ -139,6 +139,5 @@
   skin/classic/browser/privatebrowsing/private-browsing.svg    (../shared/privatebrowsing/private-browsing.svg)
   skin/classic/browser/privatebrowsing/tracking-protection-off.svg (../shared/privatebrowsing/tracking-protection-off.svg)
   skin/classic/browser/privatebrowsing/tracking-protection.svg (../shared/privatebrowsing/tracking-protection.svg)
-  skin/classic/browser/devedition/urlbar-history-dropmarker.svg (../shared/devedition/urlbar-history-dropmarker.svg)
   skin/classic/browser/urlbar-star.svg                         (../shared/urlbar-star.svg)
   skin/classic/browser/urlbar-tab.svg                          (../shared/urlbar-tab.svg)
diff --git a/application/basilisk/themes/windows/browser.css b/application/basilisk/themes/windows/browser.css
index d87b8eeafa..ee537a4b66 100644
--- a/application/basilisk/themes/windows/browser.css
+++ b/application/basilisk/themes/windows/browser.css
@@ -196,9 +196,6 @@ toolbar:-moz-lwtheme {
 
 @media not all and (-moz-windows-compositor),
        not all and (-moz-windows-default-theme) {
-  /* Please keep the menu text colors in this media block in sync with
-   * devedition.css, minus the :not(:-moz-lwtheme) condition - see Bug 1165718.
-   */
   :root[tabsintitlebar]:not([inFullscreen]):not(:-moz-lwtheme) {
     --titlebar-text-color: CaptionText;
   }
diff --git a/application/basilisk/themes/windows/devedition.css b/application/basilisk/themes/windows/devedition.css
deleted file mode 100644
index 2dc72eeeb3..0000000000
--- a/application/basilisk/themes/windows/devedition.css
+++ /dev/null
@@ -1,319 +0,0 @@
-% This Source Code Form is subject to the terms of the Mozilla Public
-% License, v. 2.0. If a copy of the MPL was not distributed with this
-% file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-%include ../shared/devedition.inc.css
-
-:root {
-  --forwardbutton-width: 29px;
-}
-
-:root[devtoolstheme="dark"],
-:root[devtoolstheme="light"] {
-   /* Matches the #browser-border-start, #browser-border-end color */
-  --chrome-nav-bar-separator-color: rgba(10, 31, 51, 0.35);
-}
-
-/* The window background is white due to no accentcolor in the lightweight
-   theme. It can't be changed to transparent when there is no compositor
-   (Win XP or 7 in classic / basic theme), or else dragging and focus become
-   broken. So instead just show the normal titlebar in that case, and override
-   the window color as transparent when the compositor is available. */
-@media not all and (-moz-windows-compositor) {
-  #main-window[tabsintitlebar] #titlebar:-moz-lwtheme {
-    visibility: visible;
-  }
-
-  #main-window {
-    background: var(--chrome-background-color) !important;
-  }
-}
-
-@media (-moz-windows-compositor) {
-  #main-window {
-    background: transparent !important;
-  }
-}
-
-#TabsToolbar::after {
-  display: none;
-}
-
-#back-button > .toolbarbutton-icon,
-#forward-button > .toolbarbutton-icon {
-  background: var(--chrome-nav-buttons-background) !important;
-  border-radius: 0 !important;
-  height: auto !important;
-  padding: var(--toolbarbutton-vertical-inner-padding) 5px !important;
-  margin: 0 !important;
-  border: 1px solid var(--chrome-nav-bar-controls-border-color) !important;
-  box-shadow: none !important;
-}
-
-#back-button > .toolbarbutton-icon {
-  /* 18px icon + 2 * 5px padding + 2 * 1px border */
-  width: 30px !important;
-}
-
-#forward-button > .toolbarbutton-icon {
-  /* 18px icon + 2 * 5px padding + 1 * 1px border */
-  width: 29px !important;
-}
-
-/* the normal theme adds box-shadow: <stuff> !important when the back-button is [open]. Fix: */
-#back-button[open="true"] > .toolbarbutton-icon {
-  box-shadow: none !important;
-}
-
-#forward-button > .toolbarbutton-icon {
-  border-inline-start: none !important;
-}
-
-/* Override a box shadow for disabled back button */
-#main-window:not([customizing]) #back-button[disabled] > .toolbarbutton-icon {
-  box-shadow: none !important;
-}
-
-/* Override !important properties for hovered back button */
-#main-window #back-button:hover:not([disabled="true"]) > .toolbarbutton-icon,
-#main-window #forward-button:hover:not([disabled="true"]) > .toolbarbutton-icon {
-  background: var(--chrome-nav-buttons-hover-background) !important;
-  box-shadow: none !important;
-}
-
-#back-button > .toolbarbutton-icon {
-  border-radius: 2px 0 0 2px !important;
-}
-
-#nav-bar .toolbarbutton-1:not([type=menu-button]),
-#nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-button,
-#nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
-  padding-top: 2px;
-  padding-bottom: 2px;
-}
-
-.tabbrowser-tab {
-  background-color: var(--tab-background-color);
-}
-
-#toolbar-menubar {
-  text-shadow: none !important;
-}
-
-:root[devtoolstheme="dark"] .findbar-closebutton,
-:root[devtoolstheme="dark"] #sidebar-header > .close-icon,
-/* Tab styling - make sure to use an inverted icon for the selected tab
-   (brighttext only covers the unselected tabs) */
-.tab-close-button[selected=true] {
-  list-style-image: url("chrome://global/skin/icons/close-inverted.png");
-}
-
-@media (min-resolution: 1.1dppx) {
-  :root[devtoolstheme="dark"] .findbar-closebutton,
-  :root[devtoolstheme="dark"] #sidebar-header > .close-icon,
-  .tab-close-button[selected=true] {
-    list-style-image: url("chrome://global/skin/icons/close-inverted@2x.png");
-  }
-}
-
-@media (-moz-os-version: windows-xp),
-       (-moz-os-version: windows-vista),
-       (-moz-os-version: windows-win7),
-       (-moz-os-version: windows-win8) {
-  :root {
-    --space-above-tabbar: 15px;
-  }
-
-  /* It'd be nice if there was an element in the scrollbox's inner content
-     that collapsed to the current width of the tabs. Since there isn't we
-     need to handle overflowing and non-overflowing tabs separately.
-
-     In the case of overflowing tabs, set a border-top on the entire container,
-     otherwise we need to set it on each element individually */
-  #main-window[sizemode=normal] .tabbrowser-tabs[overflow="true"] {
-    background-clip: padding-box;
-    border-top: 1px solid var(--chrome-nav-bar-separator-color);
-    border-inline-end: 1px solid var(--chrome-nav-bar-separator-color);
-    background-color: var(--tab-background-color); /* Make sure there is no transparent gap during tab close animation */
-  }
-
-  /* Add a border to the left of the first tab (or scroll arrow).  Using .tabbrowser-tabs
-     instead of #TabsToolbar because it will work even in customize mode. */
-  #main-window[sizemode=normal] .tabbrowser-tabs {
-    background-clip: padding-box;
-    border-inline-start: 1px solid var(--chrome-nav-bar-separator-color);
-    border-inline-end: 1px solid transparent;
-  }
-
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .tabbrowser-tab,
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .tabbrowser-arrowscrollbox > .scrollbutton-down,
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .tabbrowser-arrowscrollbox > .scrollbutton-up,
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .tabs-newtab-button {
-    background-clip: padding-box;
-    border-top: 1px solid var(--chrome-nav-bar-separator-color);
-  }
-
-  /* Allow the border-top rule to take effect */
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .tabbrowser-tab {
-    -moz-border-top-colors: none;
-  }
-
-  #main-window[sizemode=normal] .tabbrowser-tabs:not([overflow="true"]) .closing-tabs-spacer {
-    background-clip: padding-box;
-    border-inline-start: 1px solid var(--chrome-nav-bar-separator-color);
-  }
-
-  .tabs-newtab-button {
-    background: var(--tab-background-color);
-  }
-
-  /* Use default window colors when in non-maximized mode */
-  #tabbrowser-tabs,
-  #TabsToolbar,
-  #browser-panel,
-  #titlebar-content {
-    background: transparent;
-  }
-
-  /* Ensure that the entire background is styled when maximized/fullscreen */
-  #main-window:not([sizemode="normal"]):not([customizing]) #browser-panel {
-    background: var(--chrome-background-color) !important;
-  }
-
-  /* The menu items need to be visible when the entire background is styled */
-  #main-window:not([sizemode="normal"]) #main-menubar {
-    color: var(--chrome-color);
-    background-color: transparent;
-  }
-
-  #main-window[sizemode="maximized"] #main-menubar > menu:not(:-moz-window-inactive) {
-    color: inherit;
-  }
-
-  /* Use proper menu text styling in Win7 classic mode (copied from browser.css) */
-  @media not all and (-moz-windows-compositor),
-         not all and (-moz-windows-default-theme) {
-    :root[tabsintitlebar]:not([inFullscreen]) {
-      --titlebar-text-color: CaptionText;
-    }
-
-    :root[tabsintitlebar]:not([inFullscreen]):-moz-window-inactive {
-      --titlebar-text-color: InactiveCaptionText;
-    }
-
-    #main-window[tabsintitlebar] #main-menubar > menu {
-      color: inherit;
-    }
-  }
-
-  /* Use less opacity than normal since this is very dark, and on top of the default toolbar color */
-  .tabbrowser-arrowscrollbox > .scrollbutton-up[disabled],
-  .tabbrowser-arrowscrollbox > .scrollbutton-down[disabled] {
-    opacity: .6;
-  }
-
-  /* Override scrollbutton gradients in normal and hover state */
-  .tabbrowser-arrowscrollbox > .scrollbutton-down,
-  .tabbrowser-arrowscrollbox > .scrollbutton-up {
-    background-image: none !important;
-    transition: none; /* scrollbutton-down has an unwanted transition on background color */
-  }
-
-  /* Restore draggable space on the sides of tabs when maximized */
-  #main-window[sizemode="maximized"] .tabbrowser-arrowscrollbox > .arrowscrollbox-scrollbox {
-    padding-left: 15px;
-    padding-right: 15px;
-  }
-
-  /* Override the padding that's intended to compensate for tabs that can overlap border-radius on nav-bar in default theme. */
-  #main-window[sizemode=normal]:not([customizing]) #TabsToolbar {
-    padding-left: 0;
-    padding-right: 0;
-  }
-}
-
-/* Restored windows get an artificial border on windows, because the lwtheme background
- * overlaps the regular window border. That isn't the case for us, so we avoid painting
- * over the native border with our custom borders: */
-#browser-panel {
-  /* These are !important to avoid specificity-wars with the selectors that add borders here. */
-  background-image: none !important;
-  border-top: none !important;
-}
-
-#navigator-toolbox {
-  /* The side borders on the toolbox also look out-of-place because we don't paint over
-   * the native background color at all, and these are !important for the same reason as above. */
-  border-left: none !important;
-  border-right: none !important;
-}
-
-/* Disable dragging like in the default theme: */
-#main-window[tabsintitlebar] #navigator-toolbox > toolbar:not(#toolbar-menubar):not(#TabsToolbar):-moz-lwtheme {
-  -moz-window-dragging: no-drag;
-}
-
-/* The sidebar header has no background now that the background of the #browser-panel
- * has no image and is transparent. Fix: */
-.sidebar-header:-moz-lwtheme,
-#sidebar-header {
-  background-color: var(--chrome-background-color);
-  color: var(--chrome-color);
-}
-
-@media (-moz-os-version: windows-vista),
-       (-moz-os-version: windows-win7),
-       (-moz-os-version: windows-win8) {
-  /* And then we add them back on toolbars so that they don't look borderless: */
-  #main-window:not([customizing])[sizemode=normal] #navigator-toolbox::after,
-  #main-window:not([customizing])[sizemode=normal] #navigator-toolbox > toolbar:not(#toolbar-menubar):not(#TabsToolbar) {
-    border-left: 1px solid hsla(209,67%,12%,0.35);
-    border-right: 1px solid hsla(209,67%,12%,0.35);
-  }
-}
-
-@media (-moz-os-version: windows-win10) {
-  /* Always keep draggable space on the sides of tabs since there is no top margin on Win10 */
-  #main-window .tabbrowser-arrowscrollbox > .arrowscrollbox-scrollbox {
-    padding-left: 15px;
-    padding-right: 15px;
-  }
-
-  /* Force white caption buttons for the dark theme on Windows 10 */
-  :root[devtoolstheme="dark"] #titlebar-min {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#minimize-white);
-  }
-  :root[devtoolstheme="dark"] #titlebar-max {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#maximize-white);
-  }
-  #main-window[devtoolstheme="dark"][sizemode="maximized"] #titlebar-max {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#restore-white);
-  }
-  :root[devtoolstheme="dark"] #titlebar-close {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#close-white);
-  }
-
-  /* ... and normal ones for the light theme on Windows 10 */
-  :root[devtoolstheme="light"] #titlebar-min {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#minimize);
-  }
-  :root[devtoolstheme="light"] #titlebar-max {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#maximize);
-  }
-  #main-window[devtoolstheme="light"][sizemode="maximized"] #titlebar-max {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#restore);
-  }
-  :root[devtoolstheme="light"] #titlebar-close {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#close);
-  }
-
-  :root[devtoolstheme="light"] #titlebar-close:hover {
-    list-style-image: url(chrome://browser/skin/caption-buttons.svg#close-white);
-  }
-}
-
-.ac-type-icon {
-  /* Left-align the type icon in awesomebar popup results with the icon in the
-     urlbar. */
-  margin-inline-start: 13px;
-}
diff --git a/application/basilisk/themes/windows/jar.mn b/application/basilisk/themes/windows/jar.mn
index 6aeaadb89b..c25d0c9930 100644
--- a/application/basilisk/themes/windows/jar.mn
+++ b/application/basilisk/themes/windows/jar.mn
@@ -14,7 +14,6 @@ browser.jar:
   skin/classic/browser/actionicon-tab@2x.png
   skin/classic/browser/actionicon-tab-XPVista7.png
 * skin/classic/browser/browser.css
-* skin/classic/browser/devedition.css
 * skin/classic/browser/browser-lightweightTheme.css
   skin/classic/browser/caption-buttons.svg
   skin/classic/browser/click-to-play-warning-stripes.png
diff --git a/application/basilisk/tools/mozscreenshots/mozscreenshots/extension/configurations/DevEdition.jsm b/application/basilisk/tools/mozscreenshots/mozscreenshots/extension/configurations/DevEdition.jsm
deleted file mode 100644
index fd981bca3c..0000000000
--- a/application/basilisk/tools/mozscreenshots/mozscreenshots/extension/configurations/DevEdition.jsm
+++ /dev/null
@@ -1,42 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-this.EXPORTED_SYMBOLS = ["DevEdition"];
-
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
-const THEME_ID = "firefox-devedition@mozilla.org";
-
-Cu.import("resource://gre/modules/LightweightThemeManager.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/Task.jsm");
-
-this.DevEdition = {
-  init(libDir) {},
-
-  configurations: {
-    devEditionLight: {
-      applyConfig: Task.async(() => {
-        Services.prefs.setCharPref("devtools.theme", "light");
-        LightweightThemeManager.currentTheme = LightweightThemeManager.getUsedTheme(THEME_ID);
-        Services.prefs.setBoolPref("browser.devedition.theme.showCustomizeButton", true);
-      }),
-    },
-    devEditionDark: {
-      applyConfig: Task.async(() => {
-        Services.prefs.setCharPref("devtools.theme", "dark");
-        LightweightThemeManager.currentTheme = LightweightThemeManager.getUsedTheme(THEME_ID);
-        Services.prefs.setBoolPref("browser.devedition.theme.showCustomizeButton", true);
-      }),
-    },
-    devEditionOff: {
-      applyConfig: Task.async(() => {
-        Services.prefs.clearUserPref("devtools.theme");
-        LightweightThemeManager.currentTheme = null;
-        Services.prefs.clearUserPref("browser.devedition.theme.showCustomizeButton");
-      }),
-    },
-  },
-};
diff --git a/application/palemoon/base/content/browser.js b/application/palemoon/base/content/browser.js
index c3a8243642..906a681606 100644
--- a/application/palemoon/base/content/browser.js
+++ b/application/palemoon/base/content/browser.js
@@ -2445,16 +2445,12 @@ function BrowserOnAboutPageLoad(doc) {
 
     // Inject search engine and snippets URL.
     let docElt = doc.documentElement;
-    // set the following attributes BEFORE searchEngineURL, which triggers to
-    // show the snippets when it's set.
-    docElt.setAttribute("snippetsURL", AboutHomeUtils.snippetsURL);
     if (AboutHomeUtils.showKnowYourRights) {
       docElt.setAttribute("showKnowYourRights", "true");
       // Set pref to indicate we've shown the notification.
       let currentVersion = Services.prefs.getIntPref("browser.rights.version");
       Services.prefs.setBoolPref("browser.rights." + currentVersion + ".shown", true);
     }
-    docElt.setAttribute("snippetsVersion", AboutHomeUtils.snippetsVersion);
 
     function updateSearchEngine() {
       let engine = AboutHomeUtils.defaultSearchEngine;
diff --git a/application/palemoon/components/places/content/controller.js b/application/palemoon/components/places/content/controller.js
index d098271632..f4e272e2f3 100644
--- a/application/palemoon/components/places/content/controller.js
+++ b/application/palemoon/components/places/content/controller.js
@@ -444,7 +444,11 @@ PlacesController.prototype = {
             if (parentNode) {
               if (PlacesUtils.nodeIsTagQuery(parentNode))
                 nodeData["tagChild"] = true;
-              else if (this.hasCachedLivemarkInfo(parentNode))
+            }
+          } else {
+            var parentNode = node.parent;
+            if (parentNode) {
+              if (this.hasCachedLivemarkInfo(parentNode))
                 nodeData["livemarkChild"] = true;
             }
           }
diff --git a/application/palemoon/components/places/content/placesOverlay.xul b/application/palemoon/components/places/content/placesOverlay.xul
index 745990a9c2..59115a57fb 100644
--- a/application/palemoon/components/places/content/placesOverlay.xul
+++ b/application/palemoon/components/places/content/placesOverlay.xul
@@ -203,7 +203,7 @@
               accesskey="&cmd.delete.accesskey;"
               closemenu="single"
               selection="link"
-              forcehideselection="bookmark"/>
+              forcehideselection="bookmark|livemarkChild"/>
     <menuitem id="placesContext_deleteHost"
               command="placesCmd_deleteDataHost"
               label="&cmd.deleteDomainData.label;"
@@ -212,7 +212,7 @@
               selection="link|host"
               selectiontype="single"
               hideifprivatebrowsing="true"
-              forcehideselection="bookmark"/>
+              forcehideselection="bookmark|livemarkChild"/>
     <menuseparator id="placesContext_deleteSeparator"/>
     <menuitem id="placesContext_reload"
               command="placesCmd_reload"
diff --git a/config/milestone.txt b/config/milestone.txt
index 3c80f8bb5b..67b4fdd4e1 100644
--- a/config/milestone.txt
+++ b/config/milestone.txt
@@ -10,4 +10,4 @@
 # hardcoded milestones in the tree from these two files.
 #--------------------------------------------------------
 
-4.4.0
\ No newline at end of file
+4.4.1
\ No newline at end of file
diff --git a/devtools/client/framework/devtools-browser.js b/devtools/client/framework/devtools-browser.js
index 1b34e44e01..83a888ab99 100644
--- a/devtools/client/framework/devtools-browser.js
+++ b/devtools/client/framework/devtools-browser.js
@@ -330,9 +330,7 @@ var gDevToolsBrowser = exports.gDevToolsBrowser = {
       viewId: "PanelUI-developer",
       shortcutId: "key_devToolboxMenuItem",
       tooltiptext: "developer-button.tooltiptext2",
-      defaultArea: AppConstants.MOZ_DEV_EDITION ?
-                     CustomizableUI.AREA_NAVBAR :
-                     CustomizableUI.AREA_PANEL,
+      defaultArea: CustomizableUI.AREA_PANEL,
       onViewShowing: function (aEvent) {
         // Populate the subview with whatever menuitems are in the developer
         // menu. We skip menu elements, because the menu panel has no way
diff --git a/devtools/client/preferences/devtools.js b/devtools/client/preferences/devtools.js
index dea61e37f7..e817b3a18b 100644
--- a/devtools/client/preferences/devtools.js
+++ b/devtools/client/preferences/devtools.js
@@ -231,11 +231,7 @@ pref("devtools.dom.enabled", false);
 pref("devtools.webaudioeditor.inspectorWidth", 300);
 
 // Default theme ("dark" or "light")
-#ifdef MOZ_DEV_EDITION
-sticky_pref("devtools.theme", "dark");
-#else
 sticky_pref("devtools.theme", "light");
-#endif
 
 // Web console filters
 pref("devtools.webconsole.filter.error", true);
@@ -353,13 +349,8 @@ pref("devtools.editor.autocomplete", true);
 // version for each user.
 pref("devtools.telemetry.tools.opened.version", "{}");
 
-// Enable the JSON View tool (an inspector for application/json documents) on
-// Nightly and Dev. Edition.
-#ifdef RELEASE_OR_BETA
-pref("devtools.jsonview.enabled", false);
-#else
+// Enable the JSON View tool (an inspector for application/json documents)
 pref("devtools.jsonview.enabled", true);
-#endif
 
 // Enable the HTML responsive design mode for all channels.
 pref("devtools.responsive.html.enabled", true);
diff --git a/gfx/thebes/gfxMatrix.h b/gfx/thebes/gfxMatrix.h
index 9282a22dbb..4f92262cc1 100644
--- a/gfx/thebes/gfxMatrix.h
+++ b/gfx/thebes/gfxMatrix.h
@@ -112,6 +112,18 @@ public:
               _31 == 0.0 && _32 == 0.0;
     }
 
+    /* Returns true if the matrix is a rectilinear transformation (i.e.
+     * grid-aligned rectangles are transformed to grid-aligned rectangles)
+     */
+    bool IsRectilinear() const {
+      if (FuzzyEqual(_12, 0) && FuzzyEqual(_21, 0)) {
+        return true;
+      } else if (FuzzyEqual(_22, 0) && FuzzyEqual(_11, 0)) {
+        return true;
+      }
+      return false;
+    }
+
     /**
      * Inverts this matrix, if possible. Otherwise, the matrix is left
      * unchanged.
diff --git a/layout/base/FrameProperties.h b/layout/base/FrameProperties.h
index 74513abacb..3884b07bd7 100644
--- a/layout/base/FrameProperties.h
+++ b/layout/base/FrameProperties.h
@@ -202,7 +202,6 @@ public:
 
   /**
    * Get a property value. This requires a linear search through
-   * lookup (using the frame as the key) and a linear search through
    * the properties of the frame. If the frame has no such property,
    * returns zero-filled result, which means null for pointers and
    * zero for integers and floating point types.
diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index e35e027e30..e22230b410 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -5708,7 +5708,7 @@ nsDisplayTransform::GetDeltaToTransformOrigin(const nsIFrame* aFrame,
   }
 
   /* Allows us to access dimension getters by index. */
-  float coords[2];
+  float transformOrigin[2];
   TransformReferenceBox::DimensionGetter dimensionGetter[] =
     { &TransformReferenceBox::Width, &TransformReferenceBox::Height };
   TransformReferenceBox::DimensionGetter offsetGetter[] =
@@ -5718,33 +5718,33 @@ nsDisplayTransform::GetDeltaToTransformOrigin(const nsIFrame* aFrame,
     /* If the transform-origin specifies a percentage, take the percentage
      * of the size of the box.
      */
-    const nsStyleCoord &coord = display->mTransformOrigin[index];
-    if (coord.GetUnit() == eStyleUnit_Calc) {
-      const nsStyleCoord::Calc *calc = coord.GetCalcValue();
-      coords[index] =
+    const nsStyleCoord &originValue = display->mTransformOrigin[index];
+    if (originValue.GetUnit() == eStyleUnit_Calc) {
+      const nsStyleCoord::Calc *calc = originValue.GetCalcValue();
+      transformOrigin[index] =
         NSAppUnitsToFloatPixels((refBox.*dimensionGetter[index])(), aAppUnitsPerPixel) *
           calc->mPercent +
         NSAppUnitsToFloatPixels(calc->mLength, aAppUnitsPerPixel);
-    } else if (coord.GetUnit() == eStyleUnit_Percent) {
-      coords[index] =
+    } else if (originValue.GetUnit() == eStyleUnit_Percent) {
+      transformOrigin[index] =
         NSAppUnitsToFloatPixels((refBox.*dimensionGetter[index])(), aAppUnitsPerPixel) *
-        coord.GetPercentValue();
+        originValue.GetPercentValue();
     } else {
-      MOZ_ASSERT(coord.GetUnit() == eStyleUnit_Coord, "unexpected unit");
-      coords[index] =
-        NSAppUnitsToFloatPixels(coord.GetCoordValue(), aAppUnitsPerPixel);
+      MOZ_ASSERT(originValue.GetUnit() == eStyleUnit_Coord, "unexpected unit");
+      transformOrigin[index] =
+        NSAppUnitsToFloatPixels(originValue.GetCoordValue(), aAppUnitsPerPixel);
     }
 
     if (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT) {
       // SVG frames (unlike other frames) have a reference box that can be (and
       // typically is) offset from the TopLeft() of the frame. We need to
       // account for that here.
-      coords[index] +=
+      transformOrigin[index] +=
         NSAppUnitsToFloatPixels((refBox.*offsetGetter[index])(), aAppUnitsPerPixel);
     }
   }
 
-  return Point3D(coords[0], coords[1],
+  return Point3D(transformOrigin[0], transformOrigin[1],
                  NSAppUnitsToFloatPixels(display->mTransformOrigin[2].GetCoordValue(),
                                          aAppUnitsPerPixel));
 }
@@ -5917,6 +5917,17 @@ nsDisplayTransform::GetResultingTransformMatrixInternal(const FrameTransformProp
     frame && frame->IsSVGTransformed(&svgTransform, &transformFromSVGParent);
   bool hasTransformFromSVGParent =
     hasSVGTransforms && !transformFromSVGParent.IsIdentity();
+
+  bool shouldRound = true;
+
+  // An SVG frame should not have its translation rounded.
+  // Note it's possible that the SVG frame doesn't have an SVG
+  // transform but only has a CSS transform.
+  if (frame && frame->HasAnyStateBits(NS_FRAME_SVG_LAYOUT) &&
+      !(frame->GetType() == nsGkAtoms::svgOuterSVGAnonChildFrame)) {
+    shouldRound = false;
+  }
+  
   /* Transformed frames always have a transform, or are preserving 3d (and might still have perspective!) */
   if (aProperties.mTransformList) {
     result = nsStyleTransformMatrix::ReadTransforms(aProperties.mTransformList->mHead,
@@ -5994,7 +6005,7 @@ nsDisplayTransform::GetResultingTransformMatrixInternal(const FrameTransformProp
     // Otherwise we need to manually translate into our parent's coordinate
     // space.
     if (frame->IsTransformed()) {
-      nsLayoutUtils::PostTranslate(result, frame->GetPosition(), aAppUnitsPerPixel, !hasSVGTransforms);
+      nsLayoutUtils::PostTranslate(result, frame->GetPosition(), aAppUnitsPerPixel, shouldRound);
     }
     Matrix4x4 parent =
       GetResultingTransformMatrixInternal(props,
@@ -6005,7 +6016,7 @@ nsDisplayTransform::GetResultingTransformMatrixInternal(const FrameTransformProp
   }
 
   if (aFlags & OFFSET_BY_ORIGIN) {
-    nsLayoutUtils::PostTranslate(result, aOrigin, aAppUnitsPerPixel, !hasSVGTransforms);
+    nsLayoutUtils::PostTranslate(result, aOrigin, aAppUnitsPerPixel, shouldRound);
   }
 
   return result;
diff --git a/layout/reftests/svg/css-transform-svg-ref.html b/layout/reftests/svg/css-transform-svg-ref.html
new file mode 100644
index 0000000000..6167442e74
--- /dev/null
+++ b/layout/reftests/svg/css-transform-svg-ref.html
@@ -0,0 +1,10 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<style>
+</style>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20">
+    <rect id="a" x="0.49" y="0.51" width="2.5" height="2.5"/>
+    <rect id="b" x="3.5" y="3.5" width="2.5" height="2.5"/>
+</svg>
diff --git a/layout/reftests/svg/css-transform-svg.html b/layout/reftests/svg/css-transform-svg.html
new file mode 100644
index 0000000000..c1c63a8397
--- /dev/null
+++ b/layout/reftests/svg/css-transform-svg.html
@@ -0,0 +1,13 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<style>
+#a {
+  transform: scaleY(1);
+}
+</style>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20">
+    <rect id="a" x="0.49" y="0.51" width="2.5" height="2.5"/>
+    <rect id="b" x="3.5" y="3.5" width="2.5" height="2.5"/>
+</svg>
diff --git a/layout/reftests/svg/reftest.list b/layout/reftests/svg/reftest.list
index 0966286816..21e1c68a16 100644
--- a/layout/reftests/svg/reftest.list
+++ b/layout/reftests/svg/reftest.list
@@ -140,6 +140,7 @@ random == dynamic-use-nested-01b.svg dynamic-use-nested-01-ref.svg
 == fragmentIdentifier-01.xhtml pass.svg
 == linked-filter-01.svg pass.svg
 == linked-pattern-01.svg pass.svg
+pref(layout.css.devPixelsPerPx,"1.0") == svg-blurry-with-subpixel-position.html svg-blurry-with-subpixel-position-ref.html
 == use-01.svg pass.svg
 == use-01-extref.svg pass.svg
 == use-02-extref.svg use-02-extref-ref.svg
@@ -371,6 +372,7 @@ fuzzy-if(skiaContent,1,610) == textPath-03.svg pass.svg
 == text-white-space-01.svg text-white-space-01-ref.svg
 == thin-stroke-01.svg pass.svg
 == zero-stroke-01.svg pass.svg
+== css-transform-svg.html css-transform-svg-ref.html
 == tspan-dxdy-01.svg tspan-dxdy-ref.svg
 == tspan-dxdy-02.svg tspan-dxdy-ref.svg
 == tspan-dxdy-03.svg tspan-dxdy-ref.svg
diff --git a/layout/reftests/svg/svg-blurry-with-subpixel-position-ref.html b/layout/reftests/svg/svg-blurry-with-subpixel-position-ref.html
new file mode 100644
index 0000000000..c315509d72
--- /dev/null
+++ b/layout/reftests/svg/svg-blurry-with-subpixel-position-ref.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<style>
+  svg {
+    width:750px;
+    height:750px;
+    margin:3px;
+  }
+</style>
+
+<svg viewBox="0.5 0.5 750 750">
+  <path d="M3,6L277,6M3,12L277,12M3,18L277,18M3,24L277,24M3,30L277,30M3,36L277,36M3,42L277,42M3,48L277,48M3,54L277,54M3,60L277,60M3,66L277,66M3,72L277,72M3,78L277,78M3,84L277,84M3,90L277,90M3,96L277,96M3,102L277,102M3,108L277,108M3,114L277,114" style="stroke-width:1; stroke:black;" />
+  <path d="M6,3L6,277M12,3L12,277M18,3L18,277M24,3L24,277M30,3L30,277M36,3L36,277M42,3L42,277M48,3L48,277M54,3L54,277M60,3L60,277M66,3L66,277M72,3L72,277M78,3L78,277M84,3L84,277M90,3L90,277M96,3L96,277M102,3L102,277M108,3L108,277M114,3L114,277" style="stroke-width:1; stroke:black;" />
+</svg>
diff --git a/layout/reftests/svg/svg-blurry-with-subpixel-position.html b/layout/reftests/svg/svg-blurry-with-subpixel-position.html
new file mode 100644
index 0000000000..20bca71741
--- /dev/null
+++ b/layout/reftests/svg/svg-blurry-with-subpixel-position.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<style>
+  svg {
+    width:750px;
+    height:750px;
+    margin:2.5px;
+  }
+</style>
+
+<svg viewBox="0.5 0.5 750 750">
+  <path d="M3,6L277,6M3,12L277,12M3,18L277,18M3,24L277,24M3,30L277,30M3,36L277,36M3,42L277,42M3,48L277,48M3,54L277,54M3,60L277,60M3,66L277,66M3,72L277,72M3,78L277,78M3,84L277,84M3,90L277,90M3,96L277,96M3,102L277,102M3,108L277,108M3,114L277,114" style="stroke-width:1; stroke:black;" />
+  <path d="M6,3L6,277M12,3L12,277M18,3L18,277M24,3L24,277M30,3L30,277M36,3L36,277M42,3L42,277M48,3L48,277M54,3L54,277M60,3L60,277M66,3L66,277M72,3L72,277M78,3L78,277M84,3L84,277M90,3L90,277M96,3L96,277M102,3L102,277M108,3L108,277M114,3L114,277" style="stroke-width:1; stroke:black;" />
+</svg>
diff --git a/layout/style/FontFaceSet.cpp b/layout/style/FontFaceSet.cpp
index 1645adfefe..81c5ede0ec 100644
--- a/layout/style/FontFaceSet.cpp
+++ b/layout/style/FontFaceSet.cpp
@@ -583,6 +583,19 @@ FontFaceSet::StartLoad(gfxUserFontEntry* aUserFontEntry,
   nsCOMPtr<nsIStreamLoader> streamLoader;
   nsCOMPtr<nsILoadGroup> loadGroup(mDocument->GetDocumentLoadGroup());
 
+  // We're determining the security flags for font loading here based on
+  // scheme, because we want to allow fonts to be loaded using file:
+  // even if unique origins for file: access is enforced (allow CORS
+  // bypass in this case).
+  uint32_t securityFlags = 0;
+  bool isFile = false;
+  if (NS_SUCCEEDED(aFontFaceSrc->mURI->SchemeIs("file", &isFile)) &&
+      isFile) {
+    securityFlags = nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS;
+  } else {
+    securityFlags = nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS;
+  }
+
   nsCOMPtr<nsIChannel> channel;
   // Note we are calling NS_NewChannelWithTriggeringPrincipal() with both a
   // node and a principal.  This is because the document where the font is
@@ -592,7 +605,7 @@ FontFaceSet::StartLoad(gfxUserFontEntry* aUserFontEntry,
                                             aFontFaceSrc->mURI,
                                             mDocument,
                                             aUserFontEntry->GetPrincipal(),
-                                            nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS,
+                                            securityFlags,
                                             nsIContentPolicy::TYPE_FONT,
                                             loadGroup);
   NS_ENSURE_SUCCESS(rv, rv);
diff --git a/layout/svg/nsSVGOuterSVGFrame.cpp b/layout/svg/nsSVGOuterSVGFrame.cpp
index e1b97bb40b..b1ee54eb95 100644
--- a/layout/svg/nsSVGOuterSVGFrame.cpp
+++ b/layout/svg/nsSVGOuterSVGFrame.cpp
@@ -979,43 +979,56 @@ nsSVGOuterSVGAnonChildFrame::GetType() const
   return nsGkAtoms::svgOuterSVGAnonChildFrame;
 }
 
-bool
-nsSVGOuterSVGAnonChildFrame::IsSVGTransformed(Matrix* aOwnTransform,
-                                              Matrix* aFromParentTransform) const
+static Matrix
+ComputeOuterSVGAnonChildFrameTransform(const nsSVGOuterSVGAnonChildFrame* aFrame)
 {
   // Our elements 'transform' attribute is applied to our nsSVGOuterSVGFrame
   // parent, and the element's children-only transforms are applied to us, the
   // anonymous child frame. Since we are the child frame, we apply the
   // children-only transforms as if they are our own transform.
 
-  SVGSVGElement* content = static_cast<SVGSVGElement*>(mContent);
+  SVGSVGElement* content = static_cast<SVGSVGElement*>(aFrame->GetContent());
 
   if (!content->HasChildrenOnlyTransform()) {
-    return false;
+    return Matrix();
   }
 
   // Outer-<svg> doesn't use x/y, so we can pass eChildToUserSpace here.
   gfxMatrix ownMatrix =
     content->PrependLocalTransformsTo(gfxMatrix(), eChildToUserSpace);
 
-  if (ownMatrix.IsIdentity()) {
-    return false;
+  if (ownMatrix.HasNonTranslation()) {
+    // viewBox, currentScale and currentTranslate should only produce a
+    // rectilinear transform.
+    MOZ_ASSERT(ownMatrix.IsRectilinear(),
+                "Non-rectilinear transform will break the following logic");
+
+    // The nsDisplayTransform code will apply this transform to our frame,
+    // including to our frame position.  We don't want our frame position to
+    // be scaled though, so we need to correct for that in the transform.
+    CSSPoint pos = CSSPixel::FromAppUnits(aFrame->GetPosition());
+    CSSPoint scaledPos = CSSPoint(ownMatrix._11 * pos.x, ownMatrix._22 * pos.y);
+    CSSPoint deltaPos = scaledPos - pos;
+    ownMatrix *= gfxMatrix::Translation(-deltaPos.x, -deltaPos.y);
   }
 
-  if (aOwnTransform) {
-    if (ownMatrix.HasNonTranslation()) {
-      // Note: viewBox, currentScale and currentTranslate should only
-      // produce a rectilinear transform.
-      // The nsDisplayTransform code will apply this transform to our frame,
-      // including to our frame position.  We don't want our frame position to
-      // be scaled though, so we need to correct for that in the transform.
-      CSSPoint pos = CSSPixel::FromAppUnits(GetPosition());
-      CSSPoint scaledPos = CSSPoint(ownMatrix._11 * pos.x, ownMatrix._22 * pos.y);
-      CSSPoint deltaPos = scaledPos - pos;
-      ownMatrix *= gfxMatrix::Translation(-deltaPos.x, -deltaPos.y);
-    }
+  return gfx::ToMatrix(ownMatrix);
+}
 
-    *aOwnTransform = gfx::ToMatrix(ownMatrix);
+// We want this frame to be a reference frame. An easy way to achieve that is
+// to always return true from this method, even for identity transforms.
+// This frame being a reference frame ensures that the offset between this
+// <svg> element and the parent reference frame is completely absorbed by the
+// nsDisplayTransform that's created for this frame, and that this offset does
+// not affect our descendants' transforms. Consequently, if the <svg> element
+// moves, e.g. during scrolling, the transform matrices of our contents are
+// unaffected. This simplifies invalidation.
+bool
+nsSVGOuterSVGAnonChildFrame::IsSVGTransformed(Matrix* aOwnTransform,
+                                              Matrix* aFromParentTransform) const
+{
+  if (aOwnTransform) {
+    *aOwnTransform = ComputeOuterSVGAnonChildFrameTransform(this);
   }
 
   return true;
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index a55b3e5569..bd7df5d051 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -4020,6 +4020,12 @@ pref("autocomplete.ungrab_during_mode_switch", true);
 // toggling to use the XUL filepicker
 pref("ui.allow_platform_file_picker", true);
 
+// Allow for using the native GTK file picker. If the application is not run
+// with GTK_USE_PORTAL=1 this pref has no effect.
+#ifdef MOZ_WIDGET_GTK
+pref("widget.allow-gtk-native-file-chooser", false);
+#endif
+
 pref("helpers.global_mime_types_file", "/etc/mime.types");
 pref("helpers.global_mailcap_file", "/etc/mailcap");
 pref("helpers.private_mime_types_file", "~/.mime.types");
diff --git a/netwerk/base/nsIBrowserSearchService.idl b/netwerk/base/nsIBrowserSearchService.idl
index 045973e0c0..4ca052e916 100644
--- a/netwerk/base/nsIBrowserSearchService.idl
+++ b/netwerk/base/nsIBrowserSearchService.idl
@@ -7,7 +7,7 @@
 interface nsIURI;
 interface nsIInputStream;
 
-[scriptable, uuid(5799251f-5b55-4df7-a9e7-0c27812c469a)]
+[scriptable, uuid(72599f7a-3712-4b93-90e9-86127006cd68)]
 interface nsISearchSubmission : nsISupports
 {
   /**
@@ -20,6 +20,12 @@ interface nsISearchSubmission : nsISupports
    * The URI to submit a search to.
    */
   readonly attribute nsIURI uri;
+  
+  /**
+   * The POST data associated with a search submission as an
+   * application/x-www-form-urlencoded string. May be null.
+   */
+  readonly attribute AString postDataString;
 };
 
 [scriptable, uuid(620bd920-0491-48c8-99a8-d6047e64802d)]
diff --git a/old-configure.in b/old-configure.in
index 5e07dd5d11..9110ef9e64 100644
--- a/old-configure.in
+++ b/old-configure.in
@@ -5569,10 +5569,6 @@ if test "$ACCESSIBILITY" -a "$MOZ_ENABLE_GTK" ; then
     AC_DEFINE_UNQUOTED(ATK_REV_VERSION, $ATK_REV_VERSION)
 fi
 
-if test -n "$MOZ_DEV_EDITION"; then
-    AC_DEFINE(MOZ_DEV_EDITION)
-fi
-
 if test "$MOZ_DEBUG"; then
     A11Y_LOG=1
 fi
diff --git a/services/sync/modules/policies.js b/services/sync/modules/policies.js
index 2d85b1428c..48acbe2e64 100644
--- a/services/sync/modules/policies.js
+++ b/services/sync/modules/policies.js
@@ -60,20 +60,60 @@ SyncScheduler.prototype = {
   },
 
   // nextSync is in milliseconds, but prefs can't hold that much
-  get nextSync() Svc.Prefs.get("nextSync", 0) * 1000,
-  set nextSync(value) Svc.Prefs.set("nextSync", Math.floor(value / 1000)),
+  get nextSync() {
+    if (Svc.Prefs) {
+      return Svc.Prefs.get("nextSync", 0) * 1000
+    }
+  },
+  set nextSync(value) {
+    if (Svc.Prefs) {
+      Svc.Prefs.set("nextSync", Math.floor(value / 1000))
+    }
+  },
 
-  get syncInterval() Svc.Prefs.get("syncInterval", this.singleDeviceInterval),
-  set syncInterval(value) Svc.Prefs.set("syncInterval", value),
+  get syncInterval() {
+    if (Svc.Prefs) {
+      return Svc.Prefs.get("syncInterval", this.singleDeviceInterval)
+    }
+  },
+  set syncInterval(value) {
+    if (Svc.Prefs) {
+      Svc.Prefs.set("syncInterval", value)
+    }
+  },
 
-  get syncThreshold() Svc.Prefs.get("syncThreshold", SINGLE_USER_THRESHOLD),
-  set syncThreshold(value) Svc.Prefs.set("syncThreshold", value),
+  get syncThreshold() {
+    if (Svc.Prefs) {
+      return Svc.Prefs.get("syncThreshold", SINGLE_USER_THRESHOLD)
+    }
+  },
+  set syncThreshold(value) {
+    if (Svc.Prefs) {
+      Svc.Prefs.set("syncThreshold", value)
+    }
+  },
 
-  get globalScore() Svc.Prefs.get("globalScore", 0),
-  set globalScore(value) Svc.Prefs.set("globalScore", value),
+  get globalScore() {
+    if (Svc.Prefs) {
+      return Svc.Prefs.get("globalScore", 0)
+    }
+  },
+  set globalScore(value) {
+    if (Svc.Prefs) {
+      Svc.Prefs.set("globalScore", value)
+    }
+  },
 
-  get numClients() Svc.Prefs.get("numClients", 0),
-  set numClients(value) Svc.Prefs.set("numClients", value),
+  get numClients() {
+    if (Svc.Prefs) {
+      return Svc.Prefs.get("numClients", 0)
+    }
+  },
+  set numClients(value) {
+    if (Svc.Prefs) {
+      Svc.Prefs.set("numClients", value)
+    }
+  },
 
   init: function init() {
     this._log.level = Log.Level[Svc.Prefs.get("log.logger.service.main")];
@@ -523,7 +563,7 @@ SyncScheduler.prototype = {
   },
 
   get isBlocked() {
-    let until = Svc.Prefs.get("scheduler.blocked-until");
+    let until = Svc.Prefs ? Svc.Prefs.get("scheduler.blocked-until") : undefined;
     if (until === undefined) {
       return false;
     }
@@ -770,19 +810,19 @@ ErrorHandler.prototype = {
   },
 
   get currentAlertMode() {
-    return Svc.Prefs.get("errorhandler.alert.mode");
+    return Svc.Prefs ? Svc.Prefs.get("errorhandler.alert.mode") : undefined;
   },
 
   set currentAlertMode(str) {
-    return Svc.Prefs.set("errorhandler.alert.mode", str);
+    return Svc.Prefs ? Svc.Prefs.set("errorhandler.alert.mode", str) : undefined;
   },
 
   get earliestNextAlert() {
-    return Svc.Prefs.get("errorhandler.alert.earliestNext", 0) * 1000;
+    return Svc.Prefs ? Svc.Prefs.get("errorhandler.alert.earliestNext", 0) * 1000 : undefined;
   },
 
   set earliestNextAlert(msec) {
-    return Svc.Prefs.set("errorhandler.alert.earliestNext", msec / 1000);
+    return Svc.Prefs ? Svc.Prefs.set("errorhandler.alert.earliestNext", msec / 1000) : undefined;
   },
 
   clearServerAlerts: function () {
diff --git a/services/sync/modules/service.js b/services/sync/modules/service.js
index 15884aca00..804eb20cdd 100644
--- a/services/sync/modules/service.js
+++ b/services/sync/modules/service.js
@@ -296,21 +296,6 @@ Sync11Service.prototype = {
     return false;
   },
 
-  // The global "enabled" state comes from prefs, and will be set to false
-  // whenever the UI that exposes what to sync finds all Sync engines disabled.
-  get enabled() {
-    return Svc.Prefs.get("enabled");
-  },
-  set enabled(val) {
-    // There's no real reason to impose this other than to catch someone doing
-    // something we don't expect with bad consequences - all setting of this
-    // pref are in the UI code and external to this module.
-    if (val) {
-      throw new Error("Only disabling via this setter is supported");
-    }
-    Svc.Prefs.set("enabled", val);
-  },
-
   /**
    * Prepare to initialize the rest of Weave after waiting a little bit
    */
@@ -340,6 +325,8 @@ Sync11Service.prototype = {
     this._clusterManager = this.identity.createClusterManager(this);
     this.recordManager = new RecordManager(this);
 
+    this.enabled = true;
+
     this._registerEngines();
 
     let ua = Cc["@mozilla.org/network/protocol;1?name=http"].
@@ -1236,10 +1223,6 @@ Sync11Service.prototype = {
   },
 
   sync: function sync() {
-    if (!this.enabled) {
-      this._log.debug("Not syncing as Sync is disabled.");
-      return;
-    }
     let dateStr = new Date().toLocaleFormat(LOG_DATE_FORMAT);
     this._log.debug("User-Agent: " + SyncStorageRequest.prototype.userAgent);
     this._log.info("Starting sync at " + dateStr);
diff --git a/services/sync/modules/util.js b/services/sync/modules/util.js
index 7fd5a79716..73f4d8a801 100644
--- a/services/sync/modules/util.js
+++ b/services/sync/modules/util.js
@@ -321,10 +321,17 @@ this.Utils = {
    *        could not be loaded, the first argument will be undefined.
    */
   jsonLoad: Task.async(function*(filePath, that, callback) {
-    let path = OS.Path.join(OS.Constants.Path.profileDir, "weave", filePath + ".json");
+    let path;
+    try {
+      path = OS.Path.normalize(OS.Path.join(OS.Constants.Path.profileDir, "weave", filePath + ".json"));
+    } catch (e) {
+      if (that._log) {
+        that._log.debug("Path join error: " + e);
+      }
+    }
 
     if (that._log) {
-      that._log.trace("Loading json from disk: " + filePath);
+      that._log.trace("Loading json from disk: " + path);
     }
 
     let json;
@@ -341,8 +348,9 @@ this.Utils = {
         }
       }
     }
-
-    callback.call(that, json);
+    if (callback) {
+      callback.call(that, json);
+    }
   }),
 
   /**
diff --git a/services/sync/services-sync.js b/services/sync/services-sync.js
index 640fb4abc5..dfce84767f 100644
--- a/services/sync/services-sync.js
+++ b/services/sync/services-sync.js
@@ -24,10 +24,6 @@ pref("services.sync.scheduler.sync11.singleDeviceInterval", 86400); // 1 day
 
 pref("services.sync.errorhandler.networkFailureReportTimeout", 1209600); // 2 weeks
 
-// A "master" pref for Sync being enabled. Will be set to false if the sync
-// customization UI finds all our builtin engines disabled (and addons are
-// free to force this to true if they have their own engine)
-pref("services.sync.enabled", true);
 // Our engines.
 pref("services.sync.engine.addons", false);
 pref("services.sync.engine.bookmarks", true);
diff --git a/services/sync/tests/unit/test_service_login.js b/services/sync/tests/unit/test_service_login.js
index 52ee5e63ab..2ecb0a377b 100644
--- a/services/sync/tests/unit/test_service_login.js
+++ b/services/sync/tests/unit/test_service_login.js
@@ -183,7 +183,7 @@ add_test(function test_login_on_sync() {
     // This test exercises these two branches.
 
     _("We're ready to sync if locked.");
-    Svc.Prefs.set("enabled", true);
+    Service.enabled = true;
     Services.io.offline = false;
     Service.scheduler.checkSyncStatus();
     do_check_true(scheduleCalled);
diff --git a/toolkit/components/search/nsSearchService.js b/toolkit/components/search/nsSearchService.js
index 19f4048b48..f6303bca11 100644
--- a/toolkit/components/search/nsSearchService.js
+++ b/toolkit/components/search/nsSearchService.js
@@ -780,6 +780,7 @@ EngineURL.prototype = {
     }
 
     var postData = null;
+    let postDataString = null;
     if (this.method == "GET") {
       // GET method requests have no post data, and append the encoded
       // query string to the url...
@@ -787,6 +788,7 @@ EngineURL.prototype = {
         url += "?";
       url += dataString;
     } else if (this.method == "POST") {
+      postDataString = dataString;
       // POST method requests must wrap the encoded text in a MIME
       // stream and supply that as POSTDATA.
       var stringStream = Cc["@mozilla.org/io/string-input-stream;1"].
@@ -800,7 +802,7 @@ EngineURL.prototype = {
       postData.setData(stringStream);
     }
 
-    return new Submission(makeURI(url), postData);
+    return new Submission(makeURI(url), postData, postDataString);
   },
 
   _getTermsParameterName: function SRCH_EURL__getTermsParameterName() {
@@ -2409,9 +2411,10 @@ Engine.prototype = {
 };
 
 // nsISearchSubmission
-function Submission(aURI, aPostData = null) {
+function Submission(aURI, aPostData = null, aPostDataString = null) {
   this._uri = aURI;
   this._postData = aPostData;
+  this._postDataString = aPostDataString;
 }
 Submission.prototype = {
   get uri() {
@@ -2420,6 +2423,9 @@ Submission.prototype = {
   get postData() {
     return this._postData;
   },
+  get postDataString() {
+    return this._postDataString;
+  },
   QueryInterface: function SRCH_SUBM_QI(aIID) {
     if (aIID.equals(Ci.nsISearchSubmission) ||
         aIID.equals(Ci.nsISupports))
diff --git a/toolkit/modules/AppConstants.jsm b/toolkit/modules/AppConstants.jsm
index ae0eea1c48..40ceb15ba3 100644
--- a/toolkit/modules/AppConstants.jsm
+++ b/toolkit/modules/AppConstants.jsm
@@ -60,13 +60,6 @@ this.AppConstants = Object.freeze({
   false,
 #endif
 
-  MOZ_DEV_EDITION:
-#ifdef MOZ_DEV_EDITION
-  true,
-#else
-  false,
-#endif
-
   MOZ_SERVICES_HEALTHREPORT:
 #ifdef MOZ_SERVICES_HEALTHREPORT
   true,
diff --git a/toolkit/profile/nsToolkitProfileService.cpp b/toolkit/profile/nsToolkitProfileService.cpp
index 38b3a37f14..e818d27e60 100644
--- a/toolkit/profile/nsToolkitProfileService.cpp
+++ b/toolkit/profile/nsToolkitProfileService.cpp
@@ -425,22 +425,6 @@ nsToolkitProfileService::Init()
 
     nsToolkitProfile* currentProfile = nullptr;
 
-#ifdef MOZ_DEV_EDITION
-    nsCOMPtr<nsIFile> ignoreSeparateProfile;
-    rv = mAppData->Clone(getter_AddRefs(ignoreSeparateProfile));
-    if (NS_FAILED(rv))
-        return rv;
-
-    rv = ignoreSeparateProfile->AppendNative(NS_LITERAL_CSTRING("ignore-dev-edition-profile"));
-    if (NS_FAILED(rv))
-        return rv;
-
-    bool shouldIgnoreSeparateProfile;
-    rv = ignoreSeparateProfile->Exists(&shouldIgnoreSeparateProfile);
-    if (NS_FAILED(rv))
-        return rv;
-#endif
-
     unsigned int c = 0;
     bool foundAuroraDefault = false;
     for (c = 0; true; ++c) {
@@ -501,35 +485,8 @@ nsToolkitProfileService::Init()
             mChosen = currentProfile;
             this->SetDefaultProfile(currentProfile);
         }
-#ifdef MOZ_DEV_EDITION
-        // Use the dev-edition-default profile if this is an Aurora build and
-        // ignore-dev-edition-profile is not present.
-        if (name.EqualsLiteral("dev-edition-default") && !shouldIgnoreSeparateProfile) {
-            mChosen = currentProfile;
-            foundAuroraDefault = true;
-        }
-#endif
     }
 
-#ifdef MOZ_DEV_EDITION
-    if (!foundAuroraDefault && !shouldIgnoreSeparateProfile) {
-        // If a single profile exists, it may not be already marked as default.
-        // Do it now to avoid problems when we create the dev-edition-default profile.
-        if (!mChosen && mFirst && !mFirst->mNext)
-            this->SetDefaultProfile(mFirst);
-
-        // Create a default profile for aurora, if none was found.
-        nsCOMPtr<nsIToolkitProfile> profile;
-        rv = CreateProfile(nullptr,
-                           NS_LITERAL_CSTRING("dev-edition-default"),
-                           getter_AddRefs(profile));
-        if (NS_FAILED(rv)) return rv;
-        mChosen = profile;
-        rv = Flush();
-        if (NS_FAILED(rv)) return rv;
-    }
-#endif
-
     if (!mChosen && mFirst && !mFirst->mNext) // only one profile
         mChosen = mFirst;
     return NS_OK;
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index a36cf4e6c4..2b341eee02 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -2174,9 +2174,9 @@ SelectProfile(nsIProfileLock* *aResult, nsIToolkitProfileService* aProfileSvc, n
     return ShowProfileManager(aProfileSvc, aNative);
   }
 
-#ifndef MOZ_DEV_EDITION
-  // If the only existing profile is the dev-edition-profile and this is not
-  // Developer Edition, then no valid profiles were found.
+  // Dev edition leftovers:
+  // If the only existing profile is the dev-edition-profile,
+  // then no valid profiles were found.
   if (count == 1) {
     nsCOMPtr<nsIToolkitProfile> deProfile;
     // GetSelectedProfile will auto-select the only profile if there's just one
@@ -2187,7 +2187,6 @@ SelectProfile(nsIProfileLock* *aResult, nsIToolkitProfileService* aProfileSvc, n
       count = 0;
     }
   }
-#endif
 
   if (!count) {
     gDoMigration = true;
@@ -2196,25 +2195,15 @@ SelectProfile(nsIProfileLock* *aResult, nsIToolkitProfileService* aProfileSvc, n
     // create a default profile
     nsCOMPtr<nsIToolkitProfile> profile;
     nsresult rv = aProfileSvc->CreateProfile(nullptr, // choose a default dir for us
-#ifdef MOZ_DEV_EDITION
-                                             NS_LITERAL_CSTRING("dev-edition-default"),
-#else
                                              NS_LITERAL_CSTRING("default"),
-#endif
                                              getter_AddRefs(profile));
     if (NS_SUCCEEDED(rv)) {
-#ifndef MOZ_DEV_EDITION
       aProfileSvc->SetDefaultProfile(profile);
-#endif
       aProfileSvc->Flush();
       rv = profile->Lock(nullptr, aResult);
       if (NS_SUCCEEDED(rv)) {
         if (aProfileName)
-#ifdef MOZ_DEV_EDITION
-          aProfileName->AssignLiteral("dev-edition-default");
-#else
           aProfileName->AssignLiteral("default");
-#endif
         return NS_OK;
       }
     }
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js
index 00a48f3591..e449931bd8 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/import-browserjs-globals.js
@@ -32,7 +32,6 @@ const SCRIPTS = [
   "browser/base/content/browser-addons.js",
   "browser/base/content/browser-ctrlTab.js",
   "browser/base/content/browser-customization.js",
-  "browser/base/content/browser-devedition.js",
   "browser/base/content/browser-feeds.js",
   "browser/base/content/browser-fullScreenAndPointerLock.js",
   "browser/base/content/browser-fullZoom.js",
diff --git a/widget/gtk/nsFilePicker.cpp b/widget/gtk/nsFilePicker.cpp
index 172cb44448..05d8bb0f0b 100644
--- a/widget/gtk/nsFilePicker.cpp
+++ b/widget/gtk/nsFilePicker.cpp
@@ -23,6 +23,7 @@
 #include "nsNetUtil.h"
 #include "nsReadableUtils.h"
 #include "mozcontainer.h"
+#include "mozilla/Preferences.h"
 
 #include "nsFilePicker.h"
 
@@ -175,6 +176,7 @@ nsFilePicker::nsFilePicker()
   , mFileChooserDelegate(nullptr)
 #endif
 {
+  mUseNativeFileChooser = Preferences::GetBool("widget.allow-gtk-native-file-chooser", false);
 }
 
 nsFilePicker::~nsFilePicker()
@@ -197,7 +199,7 @@ ReadMultipleFiles(gpointer filename, gpointer array)
 }
 
 void
-nsFilePicker::ReadValuesFromFileChooser(GtkWidget *file_chooser)
+nsFilePicker::ReadValuesFromFileChooser(void *file_chooser)
 {
   mFiles.Clear();
 
@@ -389,19 +391,10 @@ nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
   if (!mOkButtonLabel.IsEmpty()) {
     accept_button = buttonLabel.get();
   } else {
-    accept_button = (action == GTK_FILE_CHOOSER_ACTION_SAVE) ?
-                    GTK_STOCK_SAVE : GTK_STOCK_OPEN;
+    accept_button = nullptr;
   }
 
-  GtkWidget *file_chooser =
-      gtk_file_chooser_dialog_new(title, parent_widget, action,
-                                  GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
-                                  accept_button, GTK_RESPONSE_ACCEPT,
-                                  nullptr);
-  gtk_dialog_set_alternative_button_order(GTK_DIALOG(file_chooser),
-                                          GTK_RESPONSE_ACCEPT,
-                                          GTK_RESPONSE_CANCEL,
-                                          -1);
+  void *file_chooser = GtkFileChooserNew(title.get(), parent_widget, action, accept_button);
   if (mAllowURLs) {
     gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(file_chooser), FALSE);
   }
@@ -412,11 +405,7 @@ nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
     g_signal_connect(file_chooser, "update-preview", G_CALLBACK(UpdateFilePreviewWidget), img_preview);
   }
 
-  GtkWindow *window = GTK_WINDOW(file_chooser);
-  gtk_window_set_modal(window, TRUE);
-  if (parent_widget) {
-    gtk_window_set_destroy_with_parent(window, TRUE);
-  }
+  GtkFileChooserSetModal(file_chooser, parent_widget, TRUE);
 
   NS_ConvertUTF16toUTF8 defaultName(mDefault);
   switch (mMode) {
@@ -454,18 +443,21 @@ nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
       // Otherwise, if our dialog gets destroyed, we'll lose the dialog's
       // delegate by the time this gets processed in the event loop.
       // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1166741
-      GtkDialog *dialog = GTK_DIALOG(file_chooser);
-      GtkContainer *area = GTK_CONTAINER(gtk_dialog_get_content_area(dialog));
-      gtk_container_forall(area, [](GtkWidget *widget,
-                                    gpointer data) {
-          if (GTK_IS_FILE_CHOOSER_WIDGET(widget)) {
-            auto result = static_cast<GtkFileChooserWidget**>(data);
-            *result = GTK_FILE_CHOOSER_WIDGET(widget);
-          }
-      }, &mFileChooserDelegate);
+      if (GTK_IS_DIALOG(file_chooser)) {
+        GtkDialog *dialog = GTK_DIALOG(file_chooser);
+        GtkContainer *area = GTK_CONTAINER(gtk_dialog_get_content_area(dialog));
+        gtk_container_forall(area, [](GtkWidget *widget,
+                                      gpointer data) {
+            if (GTK_IS_FILE_CHOOSER_WIDGET(widget)) {
+              auto result = static_cast<GtkFileChooserWidget**>(data);
+              *result = GTK_FILE_CHOOSER_WIDGET(widget);
+            }
+        }, &mFileChooserDelegate);
 
-      if (mFileChooserDelegate)
-        g_object_ref(mFileChooserDelegate);
+        if (mFileChooserDelegate) {
+          g_object_ref(mFileChooserDelegate);
+        }
+      }
 #endif
 
       gtk_file_chooser_set_current_folder(GTK_FILE_CHOOSER(file_chooser),
@@ -473,7 +465,9 @@ nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
     }
   }
 
-  gtk_dialog_set_default_response(GTK_DIALOG(file_chooser), GTK_RESPONSE_ACCEPT);
+  if (GTK_IS_DIALOG(file_chooser)) {
+    gtk_dialog_set_default_response(GTK_DIALOG(file_chooser), GTK_RESPONSE_ACCEPT);
+  }
 
   int32_t count = mFilters.Length();
   for (int32_t i = 0; i < count; ++i) {
@@ -517,14 +511,13 @@ nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
   mCallback = aCallback;
   NS_ADDREF_THIS();
   g_signal_connect(file_chooser, "response", G_CALLBACK(OnResponse), this);
-  g_signal_connect(file_chooser, "destroy", G_CALLBACK(OnDestroy), this);
-  gtk_widget_show(file_chooser);
+  GtkFileChooserShow(file_chooser);
 
   return NS_OK;
 }
 
 /* static */ void
-nsFilePicker::OnResponse(GtkWidget* file_chooser, gint response_id,
+nsFilePicker::OnResponse(void* file_chooser, gint response_id,
                          gpointer user_data)
 {
   static_cast<nsFilePicker*>(user_data)->
@@ -539,7 +532,7 @@ nsFilePicker::OnDestroy(GtkWidget* file_chooser, gpointer user_data)
 }
 
 void
-nsFilePicker::Done(GtkWidget* file_chooser, gint response)
+nsFilePicker::Done(void* file_chooser, gint response)
 {
   mRunning = false;
 
@@ -583,7 +576,7 @@ nsFilePicker::Done(GtkWidget* file_chooser, gint response)
   // requests that any remaining references be released, but the reference
   // count will not be decremented again if GtkWindow's reference has already
   // been released.
-  gtk_widget_destroy(file_chooser);
+  GtkFileChooserDestroy(file_chooser);
 
 #if (MOZ_WIDGET_GTK == 3)
       if (mFileChooserDelegate) {
@@ -608,3 +601,73 @@ nsFilePicker::Done(GtkWidget* file_chooser, gint response)
   }
   NS_RELEASE_THIS();
 }
+
+// All below functions available as of GTK 3.20+
+
+void *
+nsFilePicker::GtkFileChooserNew(
+        const gchar *title, GtkWindow *parent,
+        GtkFileChooserAction action,
+        const gchar *accept_label)
+{
+  static auto sGtkFileChooserNativeNewPtr = (void * (*)(
+        const gchar *, GtkWindow *,
+        GtkFileChooserAction,
+        const gchar *, const gchar *))
+      dlsym(RTLD_DEFAULT, "gtk_file_chooser_native_new");
+  if (mUseNativeFileChooser && sGtkFileChooserNativeNewPtr != nullptr) {
+    return (*sGtkFileChooserNativeNewPtr)(title, parent, action, accept_label, nullptr);
+  }
+  if (accept_label == nullptr) {
+    accept_label = (action == GTK_FILE_CHOOSER_ACTION_SAVE)
+        ? GTK_STOCK_SAVE : GTK_STOCK_OPEN;
+  }
+  GtkWidget *file_chooser = gtk_file_chooser_dialog_new(title, parent, action,
+      GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
+      accept_label, GTK_RESPONSE_ACCEPT, nullptr);
+  gtk_dialog_set_alternative_button_order(GTK_DIALOG(file_chooser),
+          GTK_RESPONSE_ACCEPT, GTK_RESPONSE_CANCEL, -1);
+  return file_chooser;
+}
+
+void
+nsFilePicker::GtkFileChooserShow(void *file_chooser)
+{
+  static auto sGtkNativeDialogShowPtr = (void (*)(void *))
+      dlsym(RTLD_DEFAULT, "gtk_native_dialog_show");
+  if (mUseNativeFileChooser && sGtkNativeDialogShowPtr != nullptr) {
+    (*sGtkNativeDialogShowPtr)(file_chooser);
+  } else {
+    g_signal_connect(file_chooser, "destroy", G_CALLBACK(OnDestroy), this);
+    gtk_widget_show(GTK_WIDGET(file_chooser));
+  }
+}
+
+void
+nsFilePicker::GtkFileChooserDestroy(void *file_chooser)
+{
+  static auto sGtkNativeDialogDestroyPtr = (void (*)(void *))
+    dlsym(RTLD_DEFAULT, "gtk_native_dialog_destroy");
+  if (mUseNativeFileChooser && sGtkNativeDialogDestroyPtr != nullptr) {
+    (*sGtkNativeDialogDestroyPtr)(file_chooser);
+  } else {
+    gtk_widget_destroy(GTK_WIDGET(file_chooser));
+  }
+}
+
+void
+nsFilePicker::GtkFileChooserSetModal(void *file_chooser,
+        GtkWindow *parent_widget, gboolean modal)
+{
+  static auto sGtkNativeDialogSetModalPtr = (void (*)(void *, gboolean))
+    dlsym(RTLD_DEFAULT, "gtk_native_dialog_set_modal");
+  if (mUseNativeFileChooser && sGtkNativeDialogSetModalPtr != nullptr) {
+    (*sGtkNativeDialogSetModalPtr)(file_chooser, modal);
+  } else {
+    GtkWindow *window = GTK_WINDOW(file_chooser);
+    gtk_window_set_modal(window, modal);
+    if (parent_widget != nullptr) {
+      gtk_window_set_destroy_with_parent(window, modal);
+    }
+  }
+}
diff --git a/widget/gtk/nsFilePicker.h b/widget/gtk/nsFilePicker.h
index 2b5042098c..e0a1d541dd 100644
--- a/widget/gtk/nsFilePicker.h
+++ b/widget/gtk/nsFilePicker.h
@@ -48,12 +48,12 @@ public:
 protected:
   virtual ~nsFilePicker();
 
-  void ReadValuesFromFileChooser(GtkWidget *file_chooser);
+  void ReadValuesFromFileChooser(void *file_chooser);
 
-  static void OnResponse(GtkWidget* dialog, gint response_id,
+  static void OnResponse(void* dialog, gint response_id,
                          gpointer user_data);
-  static void OnDestroy(GtkWidget* dialog, gpointer user_data);
-  void Done(GtkWidget* dialog, gint response_id);
+  static void OnDestroy(GtkWidget* file_chooser, gpointer user_data);
+  void Done(void* file_chooser, gint response_id);
 
   nsCOMPtr<nsIWidget>    mParentWidget;
   nsCOMPtr<nsIFilePickerShownCallback> mCallback;
@@ -74,9 +74,19 @@ protected:
 private:
   static nsIFile *mPrevDisplayDirectory;
 
+  void *GtkFileChooserNew(
+          const gchar *title, GtkWindow *parent,
+          GtkFileChooserAction action,
+          const gchar *accept_label);
+  void GtkFileChooserShow(void *file_chooser);
+  void GtkFileChooserDestroy(void *file_chooser);
+  void GtkFileChooserSetModal(void *file_chooser, GtkWindow* parent_widget,
+          gboolean modal);
+
 #if (MOZ_WIDGET_GTK == 3)
   GtkFileChooserWidget *mFileChooserDelegate;
 #endif
+  bool mUseNativeFileChooser;
 };
 
 #endif