fixup! MB 1: Mullvad Browser branding

TB 43776: Mark branding files for l10n merge.

browser/locales/l10n.toml

@@ -131,6 +131,18 @@ locales = [
     reference = "browser/branding/official/locales/en-US/**"
     l10n = "{l}browser/branding/official/**"
 
+[[paths]]
+    reference = "browser/branding/mb-alpha/locales/en-US/**"
+    l10n = "{l}browser/branding/mb-alpha/**"
+
+[[paths]]
+    reference = "browser/branding/mb-nightly/locales/en-US/**"
+    l10n = "{l}browser/branding/mb-nightly/**"
+
+[[paths]]
+    reference = "browser/branding/mb-release/locales/en-US/**"
+    l10n = "{l}browser/branding/mb-release/**"
+
 [[paths]]
     reference = "browser/extensions/formautofill/locales/en-US/**"
     l10n = "{l}browser/extensions/formautofill/**"