chromium/chrome/test/data/extensions/api_test/webnavigation/getFrame/prerender.html

<!DOCTYPE html>
<html>
<head>
<script type="speculationrules">
{
  "prerender":[
    {"source": "list",
     "urls": ["a.html"]}
  ]
}
</script>
<title>Prerender Test</title>
</head>
<body><a href="a.html" id="link">link</a></body>
</html>