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chromium/third_party/blink/renderer/core/testing/data/frameserializer/dtd/html5.html 

<!DOCTYPE html>
<html lang="en">
 <head>
  <meta charset="utf-8"/>
  <title>HTML5 DTD Test Page</title>
</head>
 <body>
  <p>HTML5 DTD Test Page</p>
 </body>
</html>