third_party/blink/web_tests/wpt_internal/task-tracking/resources/messageport-postmessage-iframe.html - manifest_repos/chromium_src - Git at Google

 <!doctype html>
 <html>
   <script>
     window.addEventListener('message', e => {
       const port = e.ports?.[0];
       port.postMessage(scheduler.taskId);
     });
   </script>
 </html>
	<!doctype html>
	<html>
	<script>
	window.addEventListener('message', e => {
	const port = e.ports?.[0];
	port.postMessage(scheduler.taskId);
	});
	</script>
	</html>