code: function getVersionFromEtag(etag) {
      var len = etag.length,
          result = etag;
  
      if (len > 1 && etag[0] === '"' && etag[len - 1] === '"') {
          result = etag.substr(1, len - 2);
      }
      return result.replace(/\\\"/g, '"');
  }
docs: Remove surrounding double quotes and unescape internal quotes