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chromium/third_party/blink/renderer/core/testing/data/viewport-device-0.5x-initial-scale.html 

<html>
  <head>
    <meta name='viewport' content='width=device-width, initial-scale=0.5' />
  </head>
  <body>
    A page with the viewport set to 0.5x scale.
  </body>
</html>