chromium/chrome/test/data/extensions/api_test/webrequest/prerendering/prerendering.html

<script>
document.addEventListener('prerenderingchange', () => {
  // Initiate a fetch request so that the test can recognize that the page
  // activation is done, but navigation events are not delivered for the
  // activation as expected. If we wrongly deliver them, it should appear before
  // this fetch events.
  fetch('initiator.html');
});
</script>
<!--
  Synchronous script loading that indicates the page is ready to activate.
-->
<script src="empty.js"/>