Codebase Browser
chromium
Go to App

chromium/chrome/test/data/reduce_accept_language/subframe_iframe_3p.html 

<html>
<head>
<link rel="stylesheet" href="https://other-site.com:44445/subresource_redirect_style.css">
</head>
<body>
<iframe src="https://other-site-b.com:44445/subframe_iframe_basic.html"></iframe>
</body>
</html>