From bb1928da055bcfd78f95bf755478c70c04376817 Mon Sep 17 00:00:00 2001
From: wuggy <ownedbywuigi@gmail.com>
Date: Sat, 19 Sep 2026 04:14:50 -0700
Subject: [PATCH] Fix "unknown localization message"

---
 toolkit/components/webextensions/ExtensionUtils.jsm | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/toolkit/components/webextensions/ExtensionUtils.jsm b/toolkit/components/webextensions/ExtensionUtils.jsm
index 04e767cb5c..2665c1a125 100644
--- a/toolkit/components/webextensions/ExtensionUtils.jsm
+++ b/toolkit/components/webextensions/ExtensionUtils.jsm
@@ -434,6 +434,13 @@ LocaleData.prototype = {
 
     options = Object.assign(defaultOptions, options);
 
+    // Some extensions probe optional localization attributes with an empty
+    // value.  There is no message to look up in that case; avoid turning the
+    // probe into a misleading "Unknown localization message" warning.
+    if (message == null || message === "") {
+      return options.defaultValue;
+    }
+
     let locales = new Set([this.BUILTIN, options.locale, this.defaultLocale]
                           .filter(locale => this.messages.has(locale)));