docs: def supported_app_locales():
      """Language codes and labels supported by current application.
  
      :return: an iterable of `(:class:`babel.Locale`, label)`, label being the
      locale language human name in current locale.
      """
      locale = _get_locale()
      codes = current_app.config["BABEL_ACCEPT_LANGUAGES"]
      return ((Locale.parse(code), locale.languages.get(code, code)) for code in codes)