);
        </script>
      </li>

      <li>
        <strong>frames === window</strong>
        <code id="testFrames"></code>
        <script type="text/partytown">
          (function () {
            const framesList = window.frames;
            const elm = document.getElementById('testFrames');
            elm.textContent = String(window === framesList);
          })();
        </script>
      </li>

      <li>
        <strong>frames['notfound'] === undefined</strong>
        <code id="testFramesIndexNot