third_party/blink/web_tests/external/wpt/https-upgrades/resources/pass-with-referrer.html - chromium/src - Git at Google

 <!DOCTYPE html>
 <html>
   <body>
     <script>
       window.onload = (event) => {
           window.opener.postMessage({
               'pass': true,
               'referrer': document.referrer},
             '*');
       };
     </script>
   </body>
 </html>
	<!DOCTYPE html>
	<html>
	<body>
	<script>
	window.onload = (event) => {
	window.opener.postMessage({
	'pass': true,
	'referrer': document.referrer},
	'*');
	};
	</script>
	</body>
	</html>