diff --git a/home/browsers/firefox.nix b/home/browsers/firefox.nix
index d6b1468..9d03d89 100644
--- a/home/browsers/firefox.nix
+++ b/home/browsers/firefox.nix
@@ -4,7 +4,8 @@ with lib;
 let
   firefox-addons = pkgs.nur.repos.rycee.firefox-addons;
 
-  prefer-dark-theme = config.gtk.gtk3.extraConfig.gtk-application-prefer-dark-theme;
+  prefer-dark-theme =
+    config.gtk.gtk3.extraConfig.gtk-application-prefer-dark-theme;
 
   sharedSettings = {
     # Privacy recommendations from https://www.privacytools.io/browsers/#about_config
@@ -29,14 +30,16 @@ let
 
     # Theme
     "ui.systemUsesDarkTheme" = prefer-dark-theme;
-    "extensions.activeThemeID" = concatStrings
-      [ "firefox-compact-"
-        (if prefer-dark-theme then "dark" else "light")
-        "@mozilla.org"
-      ];
-    "devtools.theme" = if prefer-dark-theme
-      then "dark"
-      else "light";
+    "extensions.activeThemeID" = concatStrings [
+      "firefox-compact-"
+      (if prefer-dark-theme then "dark" else "light")
+      "@mozilla.org"
+    ];
+    "devtools.theme" = if prefer-dark-theme then "dark" else "light";
+
+    # i18n
+    "intl.accept_languages" = "en-GB, en";
+    "intl.regional_prefs.use_os_locales" = true;
 
     # Other
     "browser.startup.page" = 3;
@@ -46,18 +49,14 @@ let
     "signon.rememberSignons" = false;
     "services.sync.engine.passwords" = false;
     "browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons" = false;
-    "browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features" = false;
+    "browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features" =
+      false;
     "browser.newtabpage.activity-stream.feeds.snippets" = false;
   };
-in
-{
+in {
   programs.firefox = {
     enable = true;
-    package = pkgs.firefox.override {
-      cfg = {
-        enableFXCastBridge = true;
-      };
-    };
+    package = pkgs.firefox.override { cfg = { enableFXCastBridge = true; }; };
     profiles = {
       private = {
         id = 0;
@@ -86,52 +85,54 @@ in
   };
 
   home.packages = let
-    escapeDesktopArg = arg: replaceStrings ["\""] ["\"\\\"\""] (toString arg);
+    escapeDesktopArg = arg:
+      replaceStrings [ ''"'' ] [ ''"\""'' ] (toString arg);
     makeFirefoxProfileDesktopItem = attrs:
       let
-        mkExec = with lib; { name, profile, ... }: ''
-          firefox -p "${ escapeDesktopArg profile }" --class="firefox-${ escapeDesktopArg name }"
-        '';
-      in
-        pkgs.makeDesktopItem ((removeAttrs attrs [ "profile" ]) // {
-          exec = mkExec attrs;
-          extraEntries = ''
-            StartupWMClass="${ escapeDesktopArg attrs.name }"
+        mkExec = with lib;
+          { name, profile, ... }: ''
+            firefox -p "${escapeDesktopArg profile}" --class="firefox-${
+              escapeDesktopArg name
+            }"
           '';
-        });
+      in pkgs.makeDesktopItem ((removeAttrs attrs [ "profile" ]) // {
+        exec = mkExec attrs;
+        extraEntries = ''
+          StartupWMClass="${escapeDesktopArg attrs.name}"
+        '';
+      });
     makeFirefoxWebAppDesktopItem = attrs:
       let
         # --class not yet respected: https://bugzilla.mozilla.org/show_bug.cgi?id=1606247
-        mkExec = with lib; { app, name, profile ? "private", ... }: ''
-          firefox -p "${ escapeDesktopArg profile }" --ssb="${ escapeDesktopArg app }" --class="${ escapeDesktopArg name }"
-        '';
-      in
-        pkgs.makeDesktopItem ((removeAttrs attrs [ "app" "profile" ]) // {
-          exec = mkExec attrs;
-          extraEntries = ''
-            StartupWMClass="${ escapeDesktopArg attrs.name }"
+        mkExec = with lib;
+          { app, name, profile ? "private", ... }: ''
+            firefox -p "${escapeDesktopArg profile}" --ssb="${
+              escapeDesktopArg app
+            }" --class="${escapeDesktopArg name}"
           '';
-        });
-  in
-    (with pkgs; [
-      (tor-browser-bundle-bin.override { pulseaudioSupport = true; })
-    ])
-      ++ [
-        (makeFirefoxProfileDesktopItem {
-          name = "firefox-work";
-          desktopName = "Firefox (Work)";
-          icon = "firefox"; # TODO looks different
-          profile = "work";
-        })
-        (makeFirefoxWebAppDesktopItem {
-          name = "element";
-          desktopName = "Element";
-          app = "https://app.element.io";
-        })
-        (makeFirefoxWebAppDesktopItem {
-          name = "youtube-music";
-          desktopName = "YouTube Music";
-          app = "https://music.youtube.com";
-        })
-      ];
+      in pkgs.makeDesktopItem ((removeAttrs attrs [ "app" "profile" ]) // {
+        exec = mkExec attrs;
+        extraEntries = ''
+          StartupWMClass="${escapeDesktopArg attrs.name}"
+        '';
+      });
+  in (with pkgs;
+    [ (tor-browser-bundle-bin.override { pulseaudioSupport = true; }) ]) ++ [
+      (makeFirefoxProfileDesktopItem {
+        name = "firefox-work";
+        desktopName = "Firefox (Work)";
+        icon = "firefox"; # TODO looks different
+        profile = "work";
+      })
+      (makeFirefoxWebAppDesktopItem {
+        name = "element";
+        desktopName = "Element";
+        app = "https://app.element.io";
+      })
+      (makeFirefoxWebAppDesktopItem {
+        name = "youtube-music";
+        desktopName = "YouTube Music";
+        app = "https://music.youtube.com";
+      })
+    ];
 }