--- a/testing/mozharness/mozharness/mozilla/l10n/locales.py
+++ b/testing/mozharness/mozharness/mozilla/l10n/locales.py
@@ -222,17 +222,17 @@ class LocalesMixin(ChunkingMixin):
         if c.get("user_repo_override"):
             hg_l10n_base = hg_l10n_base % {"user_repo_override": c["user_repo_override"]}
         for locale in locales:
             tag = c.get('hg_l10n_tag', 'default')
             if self.l10n_revisions.get(locale):
                 tag = self.l10n_revisions[locale]
             locale_repos.append({
                 'repo': "%s/%s" % (hg_l10n_base, locale),
-                'revision': tag,
+                'branch': tag,
                 'vcs': vcs
             })
         revs = self.vcs_checkout_repos(repo_list=locale_repos,
                                        parent_dir=parent_dir,
                                        tag_override=c.get('tag_override'))
         self.gecko_locale_revisions = revs
 
     def query_l10n_repo(self):