speculation-rules/prerender/resources/post-message-prerendering-completion-notification.html - external/github.com/web-platform-tests/wpt - Git at Google

 <!doctype html>
 <body>
 <script>
 window.parent.postMessage(`document.prerendering: ${document.prerendering}`,
                           '*');
 </script>
 </body>
	<!doctype html>
	<body>
	<script>
	window.parent.postMessage(`document.prerendering: ${document.prerendering}`,
	'*');
	</script>
	</body>