chromium/third_party/blink/web_tests/external/wpt/fenced-frame/resources/header-secFetchDest-inner.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<script src="utils.js"></script>
<title>Fenced frame content to report the value of `Sec-Fetch-Dest` header</title>

<body>
<script>
(() => {
  // This file is meant to run in a <fencedframe>. It reports back to the
  // outermost page the value of `Sec-Fetch-Dest` in the request header for
  // nested iframes inside a fenced frame.
  const [sec_fetch_dest_value_key] = parseKeylist();
  const https_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
  const https_origin_url =
      getRemoteOriginURL(
          generateURL(
              'check-header-sec-fetch-dest.py',
              [sec_fetch_dest_value_key]));

  const iframe = document.createElement('iframe');
  iframe.src = https_origin_url;
  document.body.append(iframe);
})();
</script>
</body>