code: function(s, anchor) {
      if (
          anchor === 0 &&
          s.charCodeAt(0) === 0x2F /* '/' */ &&
          s.length > 2 &&
          s.charCodeAt(s.length-1) === 0x2F /* '/' */
      ) {
          s = s + '*';
      }
      return s;
  }
docs: https://github.com/uBlockOrigin/uAssets/issues/4083#issuecomment-436914727