From d39a583127227e0e804653fea3996122ef0e1ca0 Mon Sep 17 00:00:00 2001
From: daboe01 <daboe01@googlemail.com>
Date: Tue, 24 Mar 2026 21:18:43 +0100
Subject: [PATCH 1/3] fixed: locale inference

---
 Foundation/CPLocale.j | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/Foundation/CPLocale.j b/Foundation/CPLocale.j
index c506ce299..493c62894 100644
--- a/Foundation/CPLocale.j
+++ b/Foundation/CPLocale.j
@@ -99,13 +99,21 @@ var sharedSystemLocale = nil,
 
             if (language)
             {
-                // Browsers use locale strings such as "en-US", but CPLocale uses "en_US".
-                language = language.replace("-", "_").substring(0, 5);
-                // Some browsers have "en_us" at this point, while we want "en_US".
-                language = language.substring(0, 3).toLowerCase() + language.substring(3, 5).toUpperCase();
+                // Split the BCP 47 tag into parts (e.g.,["zh", "Hans", "CN"] or ["en", "US"] or ["fr"])
+                var parts = language.split("-");
 
-                if ([availableLocaleIdentifiers indexOfObject:language] !== CPNotFound)
-                    localeIdentifier = language;
+                if (parts.length > 1)
+                {
+                    // Grab the language and the LAST part (the region code)
+                    var langCode = parts[0].toLowerCase();
+                    var regionCode = parts[parts.length - 1].toUpperCase();
+                    language = langCode + "_" + regionCode;
+                }
+                else
+                {
+                    // It's just a 2-letter code, keep it as is (or map it if your app strictly requires xx_XX)
+                    language = parts[0].toLowerCase();
+                }
             }
         }
 

From 63e3f6c3fc98fd0c40b9aa3f05a5ccfbc873ea21 Mon Sep 17 00:00:00 2001
From: daboe01 <daboe01@googlemail.com>
Date: Tue, 24 Mar 2026 21:33:24 +0100
Subject: [PATCH 2/3] fixed single region of FF

---
 Foundation/CPLocale.j | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/Foundation/CPLocale.j b/Foundation/CPLocale.j
index 493c62894..d27e20652 100644
--- a/Foundation/CPLocale.j
+++ b/Foundation/CPLocale.j
@@ -90,7 +90,7 @@ var sharedSystemLocale = nil,
     if (!sharedCurrentLocale)
     {
         var localeIdentifier = @"en_US",
-            language;
+        language;
 
         if (typeof navigator !== "undefined")
         {
@@ -104,15 +104,32 @@ var sharedSystemLocale = nil,
 
                 if (parts.length > 1)
                 {
-                    // Grab the language and the LAST part (the region code)
+                    // Chrome behavior: e.g., "de-DE" or "en-US"
                     var langCode = parts[0].toLowerCase();
                     var regionCode = parts[parts.length - 1].toUpperCase();
-                    language = langCode + "_" + regionCode;
+
+                    // Update localeIdentifier!
+                    localeIdentifier = langCode + "_" + regionCode;
                 }
                 else
                 {
-                    // It's just a 2-letter code, keep it as is (or map it if your app strictly requires xx_XX)
-                    language = parts[0].toLowerCase();
+                    // Firefox behavior: e.g., "de", "fr", "en"
+                    var langCode = parts[0].toLowerCase();
+
+                    // Create a mapping of 2-letter language codes to default region codes
+                    var defaultRegions = {
+                        "de": "DE",
+                        "en": "US",
+                        "es": "ES",
+                        "fr": "FR",
+                        "sv": "SE"
+                    };
+
+                    // Look up the default region, or fallback to the uppercased language code (e.g. "it" -> "IT")
+                    var regionCode = defaultRegions[langCode] || langCode.toUpperCase();
+
+                    // Update localeIdentifier!
+                    localeIdentifier = langCode + "_" + regionCode;
                 }
             }
         }

From c7e89d301861a4174245e4d9be950f8d8410bea1 Mon Sep 17 00:00:00 2001
From: daboe01 <daboe01@googlemail.com>
Date: Tue, 24 Mar 2026 21:34:39 +0100
Subject: [PATCH 3/3] formatting

---
 Foundation/CPLocale.j | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Foundation/CPLocale.j b/Foundation/CPLocale.j
index d27e20652..a51bb04b0 100644
--- a/Foundation/CPLocale.j
+++ b/Foundation/CPLocale.j
@@ -90,7 +90,7 @@ var sharedSystemLocale = nil,
     if (!sharedCurrentLocale)
     {
         var localeIdentifier = @"en_US",
-        language;
+            language;
 
         if (typeof navigator !== "undefined")
         {