Codebase Browser
chromium
Go to App

chromium/chrome/test/data/web_apps/nesting/nested/index.html 

<!DOCTYPE html>
<html>
<head>
  <link rel="manifest" href="manifest.json">
  <link rel="icon" href="basic-48.png">
</head>
<body>
  <h1>Nested web app</h1>
</body>
</html>