Codebase Browser
chromium
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chromium/third_party/blink/web_tests/external/wpt/resource-timing/resources/document-navigated.html 

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
  Navigated document!
<script>
  top.postMessage("navigated", "*");
</script>
</body>
</html>