chromium/third_party/blink/web_tests/external/wpt/referrer-policy/generic/link-rel-prefetch.html

<!DOCTYPE html>
<html>
  <head>
    <title>Referrer policies for resources loaded via link rel prefetch</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <!-- Common global functions for referrer-policy tests. -->
    <script src="/common/security-features/resources/common.sub.js"></script>
    <meta name="referrer" content="origin">
    <link rel="prefetch" href="/common/security-features/subresource/image.py">
  </head>
  <body>
    <p>Check that resources loaded via link rel prefetch use the referrer
    and referrer policy from the document.</p>

    <script>
      var img_url = "/common/security-features/subresource/image.py";
      promise_test((t) => timeoutPromise(t, 1000)
        .then(() => requestViaImage(img_url, null))
        .then(message => {
            assert_equals(message.headers.referer, document.location.origin + "/");
          }),
        "Prefetched image.");
    </script>

    <div id="log"></div>
  </body>
</html>