chromium/src/third_party/blink/web_tests/http/tests/cache/resources/max-age-resource-next.html

<h1></h1>
<script src="random-max-age.cgi"></script>
<script>
// Random.cgi will include a global "randomNumber".
// Send this back to our opener.
opener.postMessage(randomNumber, '*');
</script>