chromium/src/third_party/blink/web_tests/http/tests/priorities/resources/service-worker/xhr.html

<script src="../common.js"></script>
<script>
  const xhr = new XMLHttpRequest();
  xhr.open('GET', '../../../resources/dummy.html?getPriority');
  xhr.send();

  xhr.onload = reportLoaded;
  xhr.onerror = reportFailure;
</script>