Adding upstream version 1:115.7.0.upstream/1%115.7.0 upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 17:32:43 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 17:32:43 +0000
commit: 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch)
tree: a68f146d7fa01f0134297619fbe7e33db084e0aa /testing/web-platform/tests/fetch/metadata
parent: Initial commit. (diff)
download: thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz
thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip
145 files changed, 29325 insertions, 0 deletions
diff --git a/testing/web-platform/tests/fetch/metadata/META.yml b/testing/web-platform/tests/fetch/metadata/META.yml
new file mode 100644
index 0000000000..85f0a7d2ee
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/META.yml
@@ -0,0 +1,4 @@
+spec: https://w3c.github.io/webappsec-fetch-metadata/
+suggested_reviewers:
+  - mikewest
+  - iVanlIsh
diff --git a/testing/web-platform/tests/fetch/metadata/README.md b/testing/web-platform/tests/fetch/metadata/README.md
new file mode 100644
index 0000000000..34864d4a4b
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/README.md
@@ -0,0 +1,9 @@
+Fetch Metadata Tests
+====================
+
+This directory contains tests related to the Fetch Metadata proposal:
+
+:   Explainer
+::  <https://github.com/w3c/webappsec-fetch-metadata>
+:   "Spec"
+::  <https://w3c.github.io/webappsec-fetch-metadata/>
diff --git a/testing/web-platform/tests/fetch/metadata/audio-worklet.https.html b/testing/web-platform/tests/fetch/metadata/audio-worklet.https.html
new file mode 100644
index 0000000000..3b768ef0b5
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/audio-worklet.https.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script>
+
+  promise_test(async t => {
+    const nonce = token();
+    const key = "worklet-destination" + nonce;
+    const context = new AudioContext();
+
+    await context.audioWorklet.addModule("/fetch/metadata/resources/record-header.py?file=" + key);
+    const expected = {"site": "same-origin", "user": "", "mode": "cors", "dest": "audioworklet"};
+    await validate_expectations(key, expected);
+  }, "The fetch metadata for audio worklet");
+
+</script>
+<body></body>
diff --git a/testing/web-platform/tests/fetch/metadata/embed.https.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/embed.https.sub.tentative.html
new file mode 100644
index 0000000000..1900dbdf08
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/embed.https.sub.tentative.html
@@ -0,0 +1,63 @@
+<!DOCTYPE html>
+<meta charset="utf-8"/>
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body>
+
+<p>Relevant issue: <a href="https://github.com/whatwg/html/issues/513">
+&lt;embed> should support loading random HTML documents, like &lt;object>
+</a></p>
+
+<script>
+  const nonce = token();
+
+  const origins = {
+    "same-origin": "https://{{host}}:{{ports[https][0]}}",
+    "same-site":   "https://{{hosts[][www]}}:{{ports[https][0]}}",
+    "cross-site":  "https://{{hosts[alt][www]}}:{{ports[https][0]}}",
+  };
+
+  for (let site in origins) {
+    promise_test(t => {
+      return new Promise((resolve, reject) => {
+        let key = "embed-" + site + "-" + nonce;
+
+        let el = document.createElement('embed');
+        el.src = origins[site] + "/fetch/metadata/resources/record-header.py?file=" + key;
+        el.onload = _ => {
+          let expected = {"dest": "embed", "site": site, "user": "", "mode": "navigate"};
+          validate_expectations(key, expected, site + " embed")
+            .then(resolve)
+            .catch(reject);
+        };
+
+        document.body.appendChild(el);
+      })
+    }, "Wrapper: " + site + " embed");
+
+    promise_test(t => {
+      return new Promise((resolve, reject) => {
+        let key = "post-embed-" + site + "-" + nonce;
+
+        let el = document.createElement('embed');
+        el.src = "/common/blank.html";
+        el.addEventListener("load", _ => {
+          el.addEventListener("load", _ => {
+            let expected = {"dest": "embed", "site": site, "user":"", "mode":"navigate"};
+            validate_expectations(key, expected, "Navigate to " + site + " embed")
+              .then(resolve)
+              .catch(reject);
+          }, { once: true });
+
+          // Navigate the existing `<embed>`
+          window.frames[window.length - 1].location = origins[site] + "/fetch/metadata/resources/record-header.py?file=" + key;
+        }, { once: true });
+
+        document.body.appendChild(el);
+      })
+    }, "Wrapper: Navigate to " + site + " embed");
+  }
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/fetch-preflight.https.sub.any.js b/testing/web-platform/tests/fetch/metadata/fetch-preflight.https.sub.any.js
new file mode 100644
index 0000000000..d52474353b
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/fetch-preflight.https.sub.any.js
@@ -0,0 +1,29 @@
+// META: global=window,worker
+// META: script=/fetch/metadata/resources/helper.js
+
+// Site
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py",
+                {
+                  mode: "cors",
+                  headers: { 'x-test': 'testing' }
+                }, {
+          "site": "same-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Same-site fetch with preflight");
+}, "Same-site fetch with preflight");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py",
+                {
+                  mode: "cors",
+                  headers: { 'x-test': 'testing' }
+                }, {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Cross-site fetch with preflight");
+}, "Cross-site fetch with preflight");
diff --git a/testing/web-platform/tests/fetch/metadata/fetch.https.sub.any.js b/testing/web-platform/tests/fetch/metadata/fetch.https.sub.any.js
new file mode 100644
index 0000000000..aeec5cdf2d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/fetch.https.sub.any.js
@@ -0,0 +1,58 @@
+// META: global=window,worker
+// META: script=/fetch/metadata/resources/helper.js
+
+// Site
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "same-origin",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Same-origin fetch");
+}, "Same-origin fetch");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "same-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Same-site fetch");
+}, "Same-site fetch");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Cross-site fetch");
+}, "Cross-site fetch");
+
+// Mode
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {mode: "same-origin"}, {
+          "site": "same-origin",
+          "user": "",
+          "mode": "same-origin",
+          "dest": "empty"
+        }, "Same-origin mode");
+}, "Same-origin mode");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {mode: "cors"}, {
+          "site": "same-origin",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "CORS mode");
+}, "CORS mode");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {mode: "no-cors"}, {
+          "site": "same-origin",
+          "user": "",
+          "mode": "no-cors",
+          "dest": "empty"
+        }, "no-CORS mode");
+}, "no-CORS mode");
diff --git a/testing/web-platform/tests/fetch/metadata/generated/appcache-manifest.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/appcache-manifest.https.sub.html
new file mode 100644
index 0000000000..cf322fd34b
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/appcache-manifest.https.sub.html
@@ -0,0 +1,341 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/appcache-manifest.sub.https.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for Appcache manifest</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url) {
+    const iframe = document.createElement('iframe');
+    iframe.src =
+      '/fetch/metadata/resources/appcache-iframe.sub.html?manifest=' + encodeURIComponent(url);
+
+    return new Promise((resolve) => {
+        addEventListener('message', function onMessage(event) {
+          if (event.source !== iframe.contentWindow) {
+            return;
+          }
+          removeEventListener('message', onMessage);
+          resolve(event.data);
+        });
+
+        document.body.appendChild(iframe);
+      })
+      .then((message) => {
+        if (message !== 'okay') {
+          throw message;
+        }
+      })
+      .then(() => iframe.remove());
+  }
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/audioworklet.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/audioworklet.https.sub.html
new file mode 100644
index 0000000000..64fb7607e2
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/audioworklet.https.sub.html
@@ -0,0 +1,271 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/audioworklet.https.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for AudioWorklet module</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    return test_driver.bless(
+      'Enable WebAudio playback',
+      () => {
+        const audioContext = new AudioContext();
+
+        test.add_cleanup(() => audioContext.close());
+
+        return audioContext.audioWorklet.addModule(url);
+      }
+    );
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['audioworklet']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/css-font-face.https.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/generated/css-font-face.https.sub.tentative.html
new file mode 100644
index 0000000000..332effeb1f
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/css-font-face.https.sub.tentative.html
@@ -0,0 +1,230 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/css-font-face.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for CSS font-face</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  let count = 0;
+
+  function induceRequest(t, url) {
+    const id = `el-${count += 1}`;
+    const style = document.createElement('style');
+    style.appendChild(document.createTextNode(`
+      @font-face {
+        font-family: wpt-font-family${id};
+        src: url(${url});
+      }
+      #el-${id} {
+        font-family: wpt-font-family${id};
+      }
+    `));
+    const div = document.createElement('div');
+    div.setAttribute('id', 'el-' + id);
+    div.appendChild(style);
+    div.appendChild(document.createTextNode('x'));
+    document.body.appendChild(div);
+
+    t.add_cleanup(() => div.remove());
+
+    return document.fonts.ready;
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['font']);
+      });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, []))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/css-font-face.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/generated/css-font-face.sub.tentative.html
new file mode 100644
index 0000000000..8a0b90cee1
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/css-font-face.sub.tentative.html
@@ -0,0 +1,196 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/css-font-face.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for CSS font-face</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  let count = 0;
+
+  function induceRequest(t, url) {
+    const id = `el-${count += 1}`;
+    const style = document.createElement('style');
+    style.appendChild(document.createTextNode(`
+      @font-face {
+        font-family: wpt-font-family${id};
+        src: url(${url});
+      }
+      #el-${id} {
+        font-family: wpt-font-family${id};
+      }
+    `));
+    const div = document.createElement('div');
+    div.setAttribute('id', 'el-' + id);
+    div.appendChild(style);
+    div.appendChild(document.createTextNode('x'));
+    document.body.appendChild(div);
+
+    t.add_cleanup(() => div.remove());
+
+    return document.fonts.ready;
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/css-images.https.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/generated/css-images.https.sub.tentative.html
new file mode 100644
index 0000000000..3fa2401928
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/css-images.https.sub.tentative.html
@@ -0,0 +1,1384 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/css-images.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for CSS image-accepting properties</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The subtests in this file use an iframe to induce requests for CSS
+   * resources because an iframe's `onload` event is the most direct and
+   * generic mechanism to detect loading of CSS resources. As an optimization,
+   * the subtests share the same iframe and document.
+   */
+  const declarations = [];
+  const iframe = document.createElement('iframe');
+  const whenIframeReady = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-origin');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Cross-site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Cross-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Cross-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Cross-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-origin');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Origin -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Origin -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Origin -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Site -> Same Origin');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'same-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Site -> Same-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Same-Site -> Cross-Site');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_equals(headers['sec-fetch-mode'], 'no-cors');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-mode');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_equals(headers['sec-fetch-dest'], 'image');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-dest');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-user');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-user');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-user');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-user');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, []);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-user');
+
+  iframe.srcdoc = declarations.map((declaration, index) => `
+    <style>.el${index} { ${declaration} }</style><div class="el${index}"></div>`
+    ).join('');
+  document.body.appendChild(iframe);
+
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/css-images.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/generated/css-images.sub.tentative.html
new file mode 100644
index 0000000000..f1ef27cf08
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/css-images.sub.tentative.html
@@ -0,0 +1,1099 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/css-images.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for CSS image-accepting properties</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The subtests in this file use an iframe to induce requests for CSS
+   * resources because an iframe's `onload` event is the most direct and
+   * generic mechanism to detect loading of CSS resources. As an optimization,
+   * the subtests share the same iframe and document.
+   */
+  const declarations = [];
+  const iframe = document.createElement('iframe');
+  const whenIframeReady = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - HTTPS upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_equals(headers['sec-fetch-site'], 'cross-site');
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor sec-fetch-site - HTTPS downgrade-upgrade');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image sec-fetch-site - HTTPS downgrade-upgrade');
+
+  iframe.srcdoc = declarations.map((declaration, index) => `
+    <style>.el${index} { ${declaration} }</style><div class="el${index}"></div>`
+    ).join('');
+  document.body.appendChild(iframe);
+
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-a.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-a.https.sub.html
new file mode 100644
index 0000000000..dffd36c73e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-a.https.sub.html
@@ -0,0 +1,482 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-a.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "a" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const anchor = win.document.createElement('a');
+    anchor.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      anchor.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(anchor);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => anchor.click());
+    } else {
+      anchor.click();
+    }
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {"download": ""}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - attributes: download');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {"download": ""}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest - attributes: download');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: true,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - no attributes with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-a.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-a.sub.html
new file mode 100644
index 0000000000..0661de3c87
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-a.sub.html
@@ -0,0 +1,342 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-a.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "a" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const anchor = win.document.createElement('a');
+    anchor.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      anchor.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(anchor);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => anchor.click());
+    } else {
+      anchor.click();
+    }
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-area.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-area.https.sub.html
new file mode 100644
index 0000000000..be3f5f9b62
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-area.https.sub.html
@@ -0,0 +1,482 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-area.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "area" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const area = win.document.createElement('area');
+    area.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      area.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(area);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => area.click());
+    } else {
+      area.click();
+    }
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {"download": ""}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - attributes: download');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {"download": ""}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest - attributes: download');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: true,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - no attributes with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-area.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-area.sub.html
new file mode 100644
index 0000000000..5f5c338324
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-area.sub.html
@@ -0,0 +1,342 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-area.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "area" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const area = win.document.createElement('area');
+    area.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      area.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(area);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => area.click());
+    } else {
+      area.click();
+    }
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: false,
+        attributes: {}
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-audio.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-audio.https.sub.html
new file mode 100644
index 0000000000..a9d951233e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-audio.https.sub.html
@@ -0,0 +1,325 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-audio.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "audio" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const audio = document.createElement('audio');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      audio.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        audio.setAttribute('src', url);
+        audio.onload = audio.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['audio']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-audio.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-audio.sub.html
new file mode 100644
index 0000000000..2b62632ac2
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-audio.sub.html
@@ -0,0 +1,229 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-audio.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "audio" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const audio = document.createElement('audio');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      audio.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        audio.setAttribute('src', url);
+        audio.onload = audio.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-embed.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-embed.https.sub.html
new file mode 100644
index 0000000000..819bed888e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-embed.https.sub.html
@@ -0,0 +1,224 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-embed.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "embed" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    const embed = document.createElement('embed');
+    embed.setAttribute('src', url);
+    document.body.appendChild(embed);
+
+    t.add_cleanup(() => embed.remove());
+
+    return new Promise((resolve) => embed.addEventListener('load', resolve));
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['embed']);
+      });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-embed.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-embed.sub.html
new file mode 100644
index 0000000000..b6e14a55e4
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-embed.sub.html
@@ -0,0 +1,190 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-embed.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "embed" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    const embed = document.createElement('embed');
+    embed.setAttribute('src', url);
+    document.body.appendChild(embed);
+
+    t.add_cleanup(() => embed.remove());
+
+    return new Promise((resolve) => embed.addEventListener('load', resolve));
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-frame.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-frame.https.sub.html
new file mode 100644
index 0000000000..17504ff563
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-frame.https.sub.html
@@ -0,0 +1,309 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-frame.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const frame = document.createElement('frame');
+
+    const setSrc = () => frame.setAttribute('src', url);
+
+    document.body.appendChild(frame);
+    test.add_cleanup(() => frame.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        frame.onload = frame.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['frame']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        true
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-frame.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-frame.sub.html
new file mode 100644
index 0000000000..2d9a7ec97d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-frame.sub.html
@@ -0,0 +1,250 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-frame.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const frame = document.createElement('frame');
+
+    const setSrc = () => frame.setAttribute('src', url);
+
+    document.body.appendChild(frame);
+    test.add_cleanup(() => frame.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        frame.onload = frame.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-iframe.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-iframe.https.sub.html
new file mode 100644
index 0000000000..fba1c8b9e0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-iframe.https.sub.html
@@ -0,0 +1,309 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-iframe.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const iframe = document.createElement('iframe');
+
+    const setSrc = () => iframe.setAttribute('src', url);
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['iframe']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        t,
+        true
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-iframe.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-iframe.sub.html
new file mode 100644
index 0000000000..6f71cc0d25
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-iframe.sub.html
@@ -0,0 +1,250 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-iframe.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const iframe = document.createElement('iframe');
+
+    const setSrc = () => iframe.setAttribute('src', url);
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        t,
+        false
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.https.sub.html
new file mode 100644
index 0000000000..a19aa117c4
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.https.sub.html
@@ -0,0 +1,357 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-img-environment-change.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on image request triggered by change to environment</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  // The response to the request under test must describe a valid image
+  // resource in order for the `load` event to be fired.
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const iframe = document.createElement('iframe');
+    iframe.style.width = '50px';
+    document.body.appendChild(iframe);
+    t.add_cleanup(() => iframe.remove());
+    iframe.contentDocument.open();
+    iframe.contentDocument.close();
+
+    const image = iframe.contentDocument.createElement('img');
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+    iframe.contentDocument.body.appendChild(image);
+
+    image.setAttribute('srcset', `${url} 100w, /media/1x1-green.png 1w`);
+    image.setAttribute('sizes', '(max-width: 100px) 1px, (min-width: 150px) 123px');
+
+    return new Promise((resolve) => {
+        image.onload = image.onerror = resolve;
+      })
+      .then(() => {
+
+        iframe.style.width = '200px';
+
+        return new Promise((resolve) => image.onload = resolve);
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=anonymous');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=use-credentials');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.sub.html
new file mode 100644
index 0000000000..96658726ba
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-img-environment-change.sub.html
@@ -0,0 +1,270 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-img-environment-change.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on image request triggered by change to environment</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  // The response to the request under test must describe a valid image
+  // resource in order for the `load` event to be fired.
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const iframe = document.createElement('iframe');
+    iframe.style.width = '50px';
+    document.body.appendChild(iframe);
+    t.add_cleanup(() => iframe.remove());
+    iframe.contentDocument.open();
+    iframe.contentDocument.close();
+
+    const image = iframe.contentDocument.createElement('img');
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+    iframe.contentDocument.body.appendChild(image);
+
+    image.setAttribute('srcset', `${url} 100w, /media/1x1-green.png 1w`);
+    image.setAttribute('sizes', '(max-width: 100px) 1px, (min-width: 150px) 123px');
+
+    return new Promise((resolve) => {
+        image.onload = image.onerror = resolve;
+      })
+      .then(() => {
+
+        iframe.style.width = '200px';
+
+        return new Promise((resolve) => image.onload = resolve);
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-img.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-img.https.sub.html
new file mode 100644
index 0000000000..51d6e082b0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-img.https.sub.html
@@ -0,0 +1,645 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-img.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "img" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceAttr, attributes) {
+    const image = document.createElement('img');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        image.setAttribute(sourceAttr, url);
+        image.onload = image.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - src - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - srcset - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - src - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - src - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - src - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - src - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - src - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - src - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - srcset - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - srcset - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - srcset - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - srcset - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - src - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - srcset - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - src - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - srcset - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-img.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-img.sub.html
new file mode 100644
index 0000000000..5a4b152c55
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-img.sub.html
@@ -0,0 +1,456 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-img.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "img" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceAttr, attributes) {
+    const image = document.createElement('img');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        image.setAttribute(sourceAttr, url);
+        image.onload = image.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - src - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - srcset - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - src - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - srcset - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - src - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - srcset - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - src - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - srcset - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - src - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - srcset - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - src - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - srcset - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - src - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - srcset - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - src - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - srcset - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - src - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - srcset - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - src - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - srcset - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - src - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - srcset - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - src - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - srcset - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - src - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - srcset - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - src - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - srcset - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-input-image.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-input-image.https.sub.html
new file mode 100644
index 0000000000..7fa674043e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-input-image.https.sub.html
@@ -0,0 +1,229 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-input-image.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "input" element with type="button"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const input = document.createElement('input');
+    input.setAttribute('type', 'image');
+
+    document.body.appendChild(input);
+    test.add_cleanup(() => input.remove());
+
+    return new Promise((resolve) => {
+        input.onload = input.onerror = resolve;
+        input.setAttribute('src', url);
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, []), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, []), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, []), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-input-image.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-input-image.sub.html
new file mode 100644
index 0000000000..fb2a146b19
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-input-image.sub.html
@@ -0,0 +1,184 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-input-image.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "input" element with type="button"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const input = document.createElement('input');
+    input.setAttribute('type', 'image');
+
+    document.body.appendChild(input);
+    test.add_cleanup(() => input.remove());
+
+    return new Promise((resolve) => {
+        input.onload = input.onerror = resolve;
+        input.setAttribute('src', url);
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpSameSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpCrossSite']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpOrigin', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.https.sub.html
new file mode 100644
index 0000000000..b244960755
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.https.sub.html
@@ -0,0 +1,371 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-link-icon.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "link" element with rel="icon"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'icon');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      });
+  }, 'sec-fetch-mode no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {"crossorigin": ""}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {"crossorigin": "anonymous"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=anonymous');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {"crossorigin": "use-credentials"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=use-credentials');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+      });
+  }, 'sec-fetch-dest no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.sub.html
new file mode 100644
index 0000000000..e9226c190a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-link-icon.sub.html
@@ -0,0 +1,279 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-link-icon.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "link" element with rel="icon"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'icon');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.https.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.https.optional.sub.html
new file mode 100644
index 0000000000..bdd684a267
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.https.optional.sub.html
@@ -0,0 +1,559 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-link-prefetch.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "link" element with rel="prefetch"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'prefetch');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  setup(() => {
+    assert_implements_optional(document.createElement('link').relList.supports('prefetch'));
+  });
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      });
+  }, 'sec-fetch-mode no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"crossorigin": ""}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"crossorigin": "anonymous"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=anonymous');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"crossorigin": "use-credentials"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=use-credentials');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+      });
+  }, 'sec-fetch-dest no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "audio"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['audio']);
+      });
+  }, 'sec-fetch-dest attributes: as=audio');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "document"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+      });
+  }, 'sec-fetch-dest attributes: as=document');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "embed"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['embed']);
+      });
+  }, 'sec-fetch-dest attributes: as=embed');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "fetch"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['fetch']);
+      });
+  }, 'sec-fetch-dest attributes: as=fetch');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "font"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['font']);
+      });
+  }, 'sec-fetch-dest attributes: as=font');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "image"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+      });
+  }, 'sec-fetch-dest attributes: as=image');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "object"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['object']);
+      });
+  }, 'sec-fetch-dest attributes: as=object');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "script"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['script']);
+      });
+  }, 'sec-fetch-dest attributes: as=script');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "style"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['style']);
+      });
+  }, 'sec-fetch-dest attributes: as=style');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "track"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['track']);
+      });
+  }, 'sec-fetch-dest attributes: as=track');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "video"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['video']);
+      });
+  }, 'sec-fetch-dest attributes: as=video');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {"as": "worker"}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['worker']);
+      });
+  }, 'sec-fetch-dest attributes: as=worker');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, []),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user no attributes');
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.optional.sub.html
new file mode 100644
index 0000000000..c2244883cc
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-link-prefetch.optional.sub.html
@@ -0,0 +1,275 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-link-prefetch.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML "link" element with rel="prefetch"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'prefetch');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  setup(() => {
+    assert_implements_optional(document.createElement('link').relList.supports('prefetch'));
+  });
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpSameSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpCrossSite']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+      {}
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade no attributes');
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.https.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.https.optional.sub.html
new file mode 100644
index 0000000000..3a1a8eb49a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.https.optional.sub.html
@@ -0,0 +1,276 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-meta-refresh.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "meta" element with http-equiv="refresh"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.document.open();
+    win.document.write(
+      `<meta http-equiv="Refresh" content="0; URL=${url}">`
+    );
+    win.document.close();
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.optional.sub.html
new file mode 100644
index 0000000000..df3e92e2c8
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-meta-refresh.optional.sub.html
@@ -0,0 +1,225 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-meta-refresh.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "meta" element with http-equiv="refresh"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.document.open();
+    win.document.write(
+      `<meta http-equiv="Refresh" content="0; URL=${url}">`
+    );
+    win.document.close();
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-picture.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-picture.https.sub.html
new file mode 100644
index 0000000000..ba6636a019
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-picture.https.sub.html
@@ -0,0 +1,997 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-picture.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "picture" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceEl, sourceAttr, attributes) {
+    const picture = document.createElement('picture');
+    const els = {
+      img: document.createElement('img'),
+      source: document.createElement('source')
+    };
+    picture.appendChild(els.source);
+    picture.appendChild(els.img);
+    document.body.appendChild(picture);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      els.img.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        els[sourceEl].setAttribute(sourceAttr, url);
+        els.img.onload = els.img.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - img[src] - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - img[src] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - img[srcset] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - source[srcset] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[src] - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[srcset] - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - source[srcset] - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[src] - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[srcset] - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - source[srcset] - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[src] - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - img[srcset] - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - source[srcset] - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - img[src] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - img[srcset] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+        });
+  }, 'sec-fetch-dest - source[srcset] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[src] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[srcset] - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - source[srcset] - no attributes');
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-picture.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-picture.sub.html
new file mode 100644
index 0000000000..64f851c682
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-picture.sub.html
@@ -0,0 +1,721 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-picture.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "picture" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceEl, sourceAttr, attributes) {
+    const picture = document.createElement('picture');
+    const els = {
+      img: document.createElement('img'),
+      source: document.createElement('source')
+    };
+    picture.appendChild(els.source);
+    picture.appendChild(els.img);
+    document.body.appendChild(picture);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      els.img.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        els[sourceEl].setAttribute(sourceAttr, url);
+        els.img.onload = els.img.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[src] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - source[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[src] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - source[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[src] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - source[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[src] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - source[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[src] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - source[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[src] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - img[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - source[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[src] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - source[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[src] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - source[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[src] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - img[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - source[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[src] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - source[srcset] - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[src] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - source[srcset] - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[src] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - img[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - source[srcset] - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[src] - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - img[srcset] - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - source[srcset] - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'img',
+        'src',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[src] - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'img',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - img[srcset] - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        'source',
+        'srcset',
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - source[srcset] - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-script.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-script.https.sub.html
new file mode 100644
index 0000000000..dcdcba2792
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-script.https.sub.html
@@ -0,0 +1,593 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-script.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "script" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const script = document.createElement('script');
+    script.setAttribute('src', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      script.setAttribute(name, value);
+    }
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['script']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-script.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-script.sub.html
new file mode 100644
index 0000000000..a2526698fb
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-script.sub.html
@@ -0,0 +1,488 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-script.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "script" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const script = document.createElement('script');
+    script.setAttribute('src', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      script.setAttribute(name, value);
+    }
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, attributes: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        {"type": "module"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, attributes: type=module');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.https.sub.html
new file mode 100644
index 0000000000..5805b46bd0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.https.sub.html
@@ -0,0 +1,243 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-video-poster.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element "poster"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    var video = document.createElement('video');
+    video.setAttribute('poster', url);
+    document.body.appendChild(video);
+
+    const poll = () => {
+      if (video.clientWidth === 123) {
+        return;
+      }
+
+      return new Promise((resolve) => t.step_timeout(resolve, 0))
+        .then(poll);
+    };
+    t.add_cleanup(() => video.remove());
+
+    return poll();
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['image']);
+      });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.sub.html
new file mode 100644
index 0000000000..e6cc5ee7e0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-video-poster.sub.html
@@ -0,0 +1,198 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-video-poster.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element "poster"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    var video = document.createElement('video');
+    video.setAttribute('poster', url);
+    document.body.appendChild(video);
+
+    const poll = () => {
+      if (video.clientWidth === 123) {
+        return;
+      }
+
+      return new Promise((resolve) => t.step_timeout(resolve, 0))
+        .then(poll);
+    };
+    t.add_cleanup(() => video.remove());
+
+    return poll();
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpSameSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpCrossSite'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-video.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-video.https.sub.html
new file mode 100644
index 0000000000..971360dcee
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-video.https.sub.html
@@ -0,0 +1,325 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-video.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const video = document.createElement('video');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      video.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        video.setAttribute('src', url);
+        video.onload = video.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=anonymous');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - attributes: crossorigin=use-credentials');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['video']);
+        });
+  }, 'sec-fetch-dest - no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/element-video.sub.html b/testing/web-platform/tests/fetch/metadata/generated/element-video.sub.html
new file mode 100644
index 0000000000..9707413ab6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/element-video.sub.html
@@ -0,0 +1,229 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/element-video.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const video = document.createElement('video');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      video.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        video.setAttribute('src', url);
+        video.onload = video.onerror = resolve;
+      });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no attributes');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/fetch-via-serviceworker.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/fetch-via-serviceworker.https.sub.html
new file mode 100644
index 0000000000..22f930960d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/fetch-via-serviceworker.https.sub.html
@@ -0,0 +1,683 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/fetch-via-serviceworker.https.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request using the "fetch" API and passing through a Serive Worker</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const scripts = {
+    fallback: '/fetch/metadata/resources/fetch-via-serviceworker--fallback--sw.js',
+    respondWith: '/fetch/metadata/resources/fetch-via-serviceworker--respondWith--sw.js'
+  };
+
+  function induceRequest(t, url, init, script) {
+    const SCOPE = '/fetch/metadata/resources/fetch-via-serviceworker-frame.html';
+    const SCRIPT = scripts[script];
+
+    return service_worker_unregister_and_register(t, SCRIPT, SCOPE)
+      .then((registration) => {
+        t.add_cleanup(() => registration.unregister());
+
+        return wait_for_state(t, registration.installing, 'activated');
+      })
+      .then(() => with_iframe(SCOPE))
+      .then((frame) => {
+        t.add_cleanup(() => frame.remove());
+
+        return frame.contentWindow.fetch(url, init);
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - no init - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - no init - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "no-cors"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=no-cors - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "no-cors"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=no-cors - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "same-origin"},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - init: mode=same-origin - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {"mode": "same-origin"},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - init: mode=same-origin - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest - no init - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest - no init - fallback');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no init - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, []),
+        {},
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no init - fallback');
+
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/fetch.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/fetch.https.sub.html
new file mode 100644
index 0000000000..dde1daede4
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/fetch.https.sub.html
@@ -0,0 +1,302 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/fetch.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request using the "fetch" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, init) {
+    return fetch(url, init);
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite']),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site, init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"mode": "cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"mode": "no-cors"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode - init: mode=no-cors');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {"mode": "same-origin"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - init: mode=same-origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest - no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, []),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no init');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/fetch.sub.html b/testing/web-platform/tests/fetch/metadata/generated/fetch.sub.html
new file mode 100644
index 0000000000..d28ea9bb90
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/fetch.sub.html
@@ -0,0 +1,220 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/fetch.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request using the "fetch" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, init) {
+    return fetch(url, init);
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent), no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade, no init');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin']),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade, no init');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/form-submission.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/form-submission.https.sub.html
new file mode 100644
index 0000000000..988b07c74a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/form-submission.https.sub.html
@@ -0,0 +1,522 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/form-submission.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML form navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(method, url, userActivated) {
+    const windowName = String(Math.random());
+    const form = document.createElement('form');
+    const submit = document.createElement('input');
+    submit.setAttribute('type', 'submit');
+    form.appendChild(submit);
+    const win = open('about:blank', windowName);
+    form.setAttribute('method', method);
+    form.setAttribute('action', url);
+    form.setAttribute('target', windowName);
+    document.body.appendChild(form);
+
+    // Query parameters must be expressed as form values so that they are sent
+    // with the submission of forms whose method is POST.
+    Array.from(new URL(url, location.origin).searchParams)
+      .forEach(([name, value]) => {
+        const input = document.createElement('input');
+        input.setAttribute('type', 'hidden');
+        input.setAttribute('name', name);
+        input.setAttribute('value', value);
+        form.appendChild(input);
+      });
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.click(submit);
+        } else {
+          submit.click();
+        }
+      })
+      .then(() => {
+        form.remove();
+        win.close();
+      });
+  }
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = true;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - GET with user activation');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+    const userActivated = true;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - POST with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/form-submission.sub.html b/testing/web-platform/tests/fetch/metadata/generated/form-submission.sub.html
new file mode 100644
index 0000000000..f862062aeb
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/form-submission.sub.html
@@ -0,0 +1,400 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/form-submission.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML form navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(method, url, userActivated) {
+    const windowName = String(Math.random());
+    const form = document.createElement('form');
+    const submit = document.createElement('input');
+    submit.setAttribute('type', 'submit');
+    form.appendChild(submit);
+    const win = open('about:blank', windowName);
+    form.setAttribute('method', method);
+    form.setAttribute('action', url);
+    form.setAttribute('target', windowName);
+    document.body.appendChild(form);
+
+    // Query parameters must be expressed as form values so that they are sent
+    // with the submission of forms whose method is POST.
+    Array.from(new URL(url, location.origin).searchParams)
+      .forEach(([name, value]) => {
+        const input = document.createElement('input');
+        input.setAttribute('type', 'hidden');
+        input.setAttribute('name', name);
+        input.setAttribute('value', value);
+        form.appendChild(input);
+      });
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.click(submit);
+        } else {
+          submit.click();
+        }
+      })
+      .then(() => {
+        form.remove();
+        win.close();
+      });
+  }
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - POST');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('GET', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - GET');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+    const userActivated = false;
+    return induceRequest('POST', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - POST');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.html
new file mode 100644
index 0000000000..09f0113895
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.html
@@ -0,0 +1,529 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/header-link.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTTP "Link" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, rel, test) {
+    const iframe = document.createElement('iframe');
+
+    iframe.setAttribute(
+      'src',
+      '/fetch/metadata/resources/header-link.py' +
+        `?location=${encodeURIComponent(url)}&rel=${rel}`
+    );
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site rel=icon - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode rel=icon');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode rel=stylesheet');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+        });
+  }, 'sec-fetch-dest rel=icon');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=icon');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=stylesheet');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.tentative.html b/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.tentative.html
new file mode 100644
index 0000000000..307c37fbf7
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/header-link.https.sub.tentative.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/header-link.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTTP "Link" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, rel, test) {
+    const iframe = document.createElement('iframe');
+
+    iframe.setAttribute(
+      'src',
+      '/fetch/metadata/resources/header-link.py' +
+        `?location=${encodeURIComponent(url)}&rel=${rel}`
+    );
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['style']);
+        });
+  }, 'sec-fetch-dest rel=stylesheet');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/header-link.sub.html b/testing/web-platform/tests/fetch/metadata/generated/header-link.sub.html
new file mode 100644
index 0000000000..8b6cdae0ed
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/header-link.sub.html
@@ -0,0 +1,460 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/header-link.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTTP "Link" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, rel, test) {
+    const iframe = document.createElement('iframe');
+
+    iframe.setAttribute(
+      'src',
+      '/fetch/metadata/resources/header-link.py' +
+        `?location=${encodeURIComponent(url)}&rel=${rel}`
+    );
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=icon - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=stylesheet - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=icon - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=stylesheet - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=icon - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=stylesheet - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=icon - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=stylesheet - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=icon - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=stylesheet - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=icon - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode rel=stylesheet - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=icon - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=stylesheet - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=icon - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=stylesheet - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=icon - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest rel=stylesheet - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=icon - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=stylesheet - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=icon - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=stylesheet - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=icon - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user rel=stylesheet - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=icon - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site rel=stylesheet - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'icon',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=icon - HTTPS downgrade-upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], {mime: 'text/html'}),
+        'stylesheet',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site rel=stylesheet - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/header-refresh.https.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/header-refresh.https.optional.sub.html
new file mode 100644
index 0000000000..e63ee423cd
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/header-refresh.https.optional.sub.html
@@ -0,0 +1,273 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/header-refresh.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTTP "Refresh" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.location = `/common/refresh.py?location=${encodeURIComponent(url)}`
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/header-refresh.optional.sub.html b/testing/web-platform/tests/fetch/metadata/generated/header-refresh.optional.sub.html
new file mode 100644
index 0000000000..4674ada9c6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/header-refresh.optional.sub.html
@@ -0,0 +1,222 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/header-refresh.optional.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTTP "Refresh" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.location = `/common/refresh.py?location=${encodeURIComponent(url)}`
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpSameSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpCrossSite'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.https.sub.html
new file mode 100644
index 0000000000..72d60fc30c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.https.sub.html
@@ -0,0 +1,254 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/script-module-import-dynamic.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dynamic ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['script']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.sub.html b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.sub.html
new file mode 100644
index 0000000000..088720c23e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-dynamic.sub.html
@@ -0,0 +1,214 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/script-module-import-dynamic.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dynamic ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.https.sub.html
new file mode 100644
index 0000000000..cea3464f80
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.https.sub.html
@@ -0,0 +1,288 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/script-module-import-static.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for static ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url) {
+    const script = document.createElement('script');
+    script.setAttribute('type', 'module');
+    script.setAttribute(
+      'src',
+      '/fetch/metadata/resources/es-module.sub.js?moduleId=' + encodeURIComponent(url)
+    );
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsCrossSite', 'httpsSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsCrossSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpsSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpsCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsSameSite', 'httpsSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsSameSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, [], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, [], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['script']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, [], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.sub.html b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.sub.html
new file mode 100644
index 0000000000..0f94f71cf6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/script-module-import-static.sub.html
@@ -0,0 +1,246 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/script-module-import-static.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for static ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url) {
+    const script = document.createElement('script');
+    script.setAttribute('type', 'module');
+    script.setAttribute(
+      'src',
+      '/fetch/metadata/resources/es-module.sub.js?moduleId=' + encodeURIComponent(url)
+    );
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpSameSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpCrossSite'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/serviceworker.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/serviceworker.https.sub.html
new file mode 100644
index 0000000000..12e37369a4
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/serviceworker.https.sub.html
@@ -0,0 +1,170 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/serviceworker.https.sub.html
+-->
+<!DOCTYPE html>
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for Service Workers</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(t, url, options, event, clear) {
+    // Register a service worker and check the request header.
+    return navigator.serviceWorker.register(url, options)
+      .then((registration) => {
+        t.add_cleanup(() => registration.unregister());
+        if (event === 'register') {
+          return;
+        }
+        return clear().then(() => registration.update());
+      });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no options - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin, no options - updating');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {"type": "classic"}, 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - options: type=classic - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {"type": "classic"}, 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - options: type=classic - updating');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - no options - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - no options - updating');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['serviceworker']);
+        });
+  }, 'sec-fetch-dest - no options - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['serviceworker']);
+        });
+  }, 'sec-fetch-dest - no options - updating');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no options - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, {}, 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no options - updating');
+  </script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/svg-image.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/svg-image.https.sub.html
new file mode 100644
index 0000000000..b059eb3145
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/svg-image.https.sub.html
@@ -0,0 +1,367 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/svg-image.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for SVG "image" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
+    svg.setAttributeNS(
+      "http://www.w3.org/2000/xmlns/",
+      "xmlns:xlink",
+      "http://www.w3.org/1999/xlink"
+    );
+    const image = document.createElementNS("http://www.w3.org/2000/svg", "image");
+    image.setAttribute("href", url);
+    svg.appendChild(image);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    document.body.appendChild(svg);
+    t.add_cleanup(() => svg.remove());
+
+    return new Promise((resolve, reject) => {
+      image.onload = resolve;
+      image.onerror = reject;
+    });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same Origin no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Same-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+      });
+  }, 'sec-fetch-mode no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": ""}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": "anonymous"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=anonymous');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {"crossorigin": "use-credentials"}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['cors']);
+      });
+  }, 'sec-fetch-mode attributes: crossorigin=use-credentials');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['empty']);
+      });
+  }, 'sec-fetch-dest no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/svg-image.sub.html b/testing/web-platform/tests/fetch/metadata/generated/svg-image.sub.html
new file mode 100644
index 0000000000..a28bbb12eb
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/svg-image.sub.html
@@ -0,0 +1,265 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/svg-image.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for SVG "image" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
+    svg.setAttributeNS(
+      "http://www.w3.org/2000/xmlns/",
+      "xmlns:xlink",
+      "http://www.w3.org/1999/xlink"
+    );
+    const image = document.createElementNS("http://www.w3.org/2000/svg", "image");
+    image.setAttribute("href", url);
+    svg.appendChild(image);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    document.body.appendChild(svg);
+    t.add_cleanup(() => svg.remove());
+
+    return new Promise((resolve, reject) => {
+      image.onload = resolve;
+      image.onerror = reject;
+    });
+  }
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+      });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+      });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpSameSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpCrossSite'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+      });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+      });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS upgrade no attributes');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], params),
+        {}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+      });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade no attributes');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/window-history.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/window-history.https.sub.html
new file mode 100644
index 0000000000..c2b3079a6d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/window-history.https.sub.html
@@ -0,0 +1,237 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/window-history.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for navigation via the HTML History API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const whenDone = (win) => {
+    return new Promise((resolve) => {
+      addEventListener('message', function handle(event) {
+        if (event.source === win) {
+          resolve();
+          removeEventListener('message', handle);
+        }
+      });
+    })
+  };
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately behind the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.back`.
+   */
+  function induceBackRequest(url, test, clear) {
+    const win = window.open(url);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(clear)
+      .then(() => win.history.back())
+      .then(() => whenDone(win));
+  }
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately ahead of the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.forward`.
+   */
+  function induceForwardRequest(url, test, clear) {
+    const win = window.open(messageOpenerUrl);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(() => win.location = url)
+      .then(() => whenDone(win))
+      .then(clear)
+      .then(() => win.history.go(-2))
+      .then(() => whenDone(win))
+      .then(() => win.history.forward())
+      .then(() => whenDone(win));
+  }
+
+  const messageOpenerUrl = new URL(
+    '/fetch/metadata/resources/message-opener.html', location
+  );
+  // For these tests to function, replacement must *not* be enabled during
+  // navigation. Assignment must therefore take place after the document has
+  // completely loaded [1]. This event is not directly observable, but it is
+  // scheduled as a task immediately following the global object's `load`
+  // event [2]. By queuing a task during the dispatch of the `load` event,
+  // navigation can be consistently triggered without replacement.
+  //
+  // [1] https://html.spec.whatwg.org/multipage/history.html#location-object-setter-navigate
+  // [2] https://html.spec.whatwg.org/multipage/parsing.html#the-end
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>
+      window.addEventListener('load', () => {
+        set`+`Timeout(() => location.assign('${messageOpenerUrl}'));
+      });
+    <`+`/script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - history.forward');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/window-history.sub.html b/testing/web-platform/tests/fetch/metadata/generated/window-history.sub.html
new file mode 100644
index 0000000000..333d90c286
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/window-history.sub.html
@@ -0,0 +1,360 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/window-history.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for navigation via the HTML History API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const whenDone = (win) => {
+    return new Promise((resolve) => {
+      addEventListener('message', function handle(event) {
+        if (event.source === win) {
+          resolve();
+          removeEventListener('message', handle);
+        }
+      });
+    })
+  };
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately behind the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.back`.
+   */
+  function induceBackRequest(url, test, clear) {
+    const win = window.open(url);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(clear)
+      .then(() => win.history.back())
+      .then(() => whenDone(win));
+  }
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately ahead of the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.forward`.
+   */
+  function induceForwardRequest(url, test, clear) {
+    const win = window.open(messageOpenerUrl);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(() => win.location = url)
+      .then(() => whenDone(win))
+      .then(clear)
+      .then(() => win.history.go(-2))
+      .then(() => whenDone(win))
+      .then(() => win.history.forward())
+      .then(() => whenDone(win));
+  }
+
+  const messageOpenerUrl = new URL(
+    '/fetch/metadata/resources/message-opener.html', location
+  );
+  // For these tests to function, replacement must *not* be enabled during
+  // navigation. Assignment must therefore take place after the document has
+  // completely loaded [1]. This event is not directly observable, but it is
+  // scheduled as a task immediately following the global object's `load`
+  // event [2]. By queuing a task during the dispatch of the `load` event,
+  // navigation can be consistently triggered without replacement.
+  //
+  // [1] https://html.spec.whatwg.org/multipage/history.html#location-object-setter-navigate
+  // [2] https://html.spec.whatwg.org/multipage/parsing.html#the-end
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>
+      window.addEventListener('load', () => {
+        set`+`Timeout(() => location.assign('${messageOpenerUrl}'));
+      });
+    <`+`/script>`
+  };
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - history.forward');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - history.back');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - history.forward');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/window-location.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/window-location.https.sub.html
new file mode 100644
index 0000000000..4a0d2fdc06
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/window-location.https.sub.html
@@ -0,0 +1,1184 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/window-location.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for navigation via the HTML Location API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, navigate, userActivated) {
+    const win = window.open();
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.bless('enable user activation', () => {
+            navigate(win, url);
+          });
+        } else {
+          navigate(win, url);
+        }
+      })
+      .then(() => win.close());
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsCrossSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsSameSite', 'httpsCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['navigate']);
+        });
+  }, 'sec-fetch-mode - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['document']);
+        });
+  }, 'sec-fetch-dest - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, true)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - location with user activation');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, true)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - location.href with user activation');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, true)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - location.assign with user activation');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, true)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-user');
+          assert_array_equals(headers['sec-fetch-user'], ['?1']);
+        });
+  }, 'sec-fetch-user - location.replace with user activation');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/window-location.sub.html b/testing/web-platform/tests/fetch/metadata/generated/window-location.sub.html
new file mode 100644
index 0000000000..bb3e6805cb
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/window-location.sub.html
@@ -0,0 +1,894 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/window-location.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for navigation via the HTML Location API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, navigate, userActivated) {
+    const win = window.open();
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.bless('enable user activation', () => {
+            navigate(win, url);
+          });
+        } else {
+          navigate(win, url);
+        }
+      })
+      .then(() => win.close());
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpSameSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpCrossSite'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent) - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade - location.replace');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.href');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.assign');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, false)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade - location.replace');
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.https.sub.html
new file mode 100644
index 0000000000..86f1760755
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.https.sub.html
@@ -0,0 +1,118 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/worker-dedicated-constructor.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "Worker" constructor</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(url, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url, {"type": "module"})
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['same-origin']);
+        });
+  }, 'sec-fetch-mode - options: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['worker']);
+        });
+  }, 'sec-fetch-dest - no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url, {"type": "module"})
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['worker']);
+        });
+  }, 'sec-fetch-dest - options: type=module');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url, {"type": "module"})
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - options: type=module');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.sub.html b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.sub.html
new file mode 100644
index 0000000000..69ac7682a5
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-constructor.sub.html
@@ -0,0 +1,204 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/worker-dedicated-constructor.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "Worker" constructor</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(url, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpOrigin'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpSameSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpCrossSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpOrigin'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpSameSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpCrossSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpOrigin'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpSameSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpCrossSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpOrigin'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpSameSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination, no options');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      ['httpCrossSite'],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination, no options');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.https.sub.html b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.https.sub.html
new file mode 100644
index 0000000000..0cd9f35d58
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.https.sub.html
@@ -0,0 +1,268 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/worker-dedicated-importscripts.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "importScripts" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    const src = `
+      importScripts('${url}');
+      postMessage('done');
+    `;
+    const workerUrl = URL.createObjectURL(
+      new Blob([src], { type: 'application/javascript' })
+    );
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(workerUrl, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site -> Same-Origin redirect');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsCrossSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Cross-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-origin']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Origin -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same Origin');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['same-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Same-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsSameSite', 'httpsCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - Same-Site -> Cross-Site');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-mode');
+          assert_array_equals(headers['sec-fetch-mode'], ['no-cors']);
+        });
+  }, 'sec-fetch-mode');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-dest');
+          assert_array_equals(headers['sec-fetch-dest'], ['script']);
+        });
+  }, 'sec-fetch-dest');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.sub.html b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.sub.html
new file mode 100644
index 0000000000..0555bbaf43
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/generated/worker-dedicated-importscripts.sub.html
@@ -0,0 +1,228 @@
+<!DOCTYPE html>
+<!--
+This test was procedurally generated. Please do not modify it directly.
+Sources:
+- fetch/metadata/tools/fetch-metadata.conf.yml
+- fetch/metadata/tools/templates/worker-dedicated-importscripts.sub.html
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "importScripts" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    const src = `
+      importScripts('${url}');
+      postMessage('done');
+    `;
+    const workerUrl = URL.createObjectURL(
+      new Blob([src], { type: 'application/javascript' })
+    );
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(workerUrl, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-mode');
+        });
+  }, 'sec-fetch-mode - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-dest');
+        });
+  }, 'sec-fetch-dest - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-origin destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpSameSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy same-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpCrossSite'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-user');
+        });
+  }, 'sec-fetch-user - Not sent to non-trustworthy cross-site destination');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_not_own_property(headers, 'sec-fetch-site');
+        });
+  }, 'sec-fetch-site - HTTPS downgrade (header not sent)');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS upgrade');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, ['httpsOrigin', 'httpOrigin', 'httpsOrigin'], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+          assert_own_property(headers, 'sec-fetch-site');
+          assert_array_equals(headers['sec-fetch-site'], ['cross-site']);
+        });
+  }, 'sec-fetch-site - HTTPS downgrade-upgrade');
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/navigation.https.sub.html b/testing/web-platform/tests/fetch/metadata/navigation.https.sub.html
new file mode 100644
index 0000000000..32c9cf77f9
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/navigation.https.sub.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script>
+  test(t => {
+    let expected = {
+      "mode": "navigate",
+      "site": "none",
+      "dest": "document"
+    };
+
+    let actual = {
+      "mode": "{{headers[sec-fetch-mode]}}",
+      "site": "{{headers[sec-fetch-site]}}",
+      // Skipping `Sec-Fetch-User`, as the test harness isn't consistent here.
+      "dest": "{{headers[sec-fetch-dest]}}"
+    };
+
+    assert_header_equals(actual, expected);
+  }, "This page's top-level navigation.");
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/object.https.sub.html b/testing/web-platform/tests/fetch/metadata/object.https.sub.html
new file mode 100644
index 0000000000..fae5b37b59
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/object.https.sub.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<meta charset="utf-8"/>
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body>
+<script>
+  let nonce = token();
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "object-same-origin" + nonce;
+
+      let e = document.createElement('object');
+      e.data = "https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"same-origin", "user":"", "mode":"navigate", "dest": "object"};
+        validate_expectations(key, expected, "Same-Origin object")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Same-Origin object");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "object-same-site" + nonce;
+
+      let e = document.createElement('object');
+      e.data = "https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"same-site", "user":"", "mode":"navigate", "dest": "object"};
+        validate_expectations(key, expected, "Same-Site object")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Same-Site object");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "object-cross-site" + nonce;
+
+      let e = document.createElement('object');
+      e.data = "https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"cross-site", "user":"", "mode":"navigate", "dest": "object"};
+        validate_expectations(key, expected, "Cross-Site object")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Cross-Site object");
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/paint-worklet.https.html b/testing/web-platform/tests/fetch/metadata/paint-worklet.https.html
new file mode 100644
index 0000000000..49fc7765f6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/paint-worklet.https.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script>
+
+  promise_test(async t => {
+    const nonce = token();
+    const key = "worklet-destination" + nonce;
+
+    await CSS.paintWorklet.addModule("/fetch/metadata/resources/record-header.py?file=" + key);
+    const expected = {"site": "same-origin", "user": "", "mode": "cors", "dest": "paintworklet"};
+    await validate_expectations(key, expected);
+  }, "The fetch metadata for paint worklet");
+
+</script>
+<body></body>
diff --git a/testing/web-platform/tests/fetch/metadata/portal.https.sub.html b/testing/web-platform/tests/fetch/metadata/portal.https.sub.html
new file mode 100644
index 0000000000..55b555a1b8
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/portal.https.sub.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/resources/testdriver.js></script>
+<script src=/resources/testdriver-vendor.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script src=/portals/resources/stash-utils.sub.js></script>
+<body>
+<script>
+  const USER = true;
+  const FORCED = false;
+
+  function create_test(host, expectations) {
+    async_test(t => {
+      assert_implements("HTMLPortalElement" in window, "Portals are not supported.");
+
+      let p = document.createElement('portal');
+      const key = token();
+      StashUtils.takeValue(key).then(t.step_func_done(value => {
+        assert_header_equals(value, expectations, `{{host}} -> ${host} portal`);
+      }));
+
+      let url = `https://${host}/fetch/metadata/resources/post-to-owner.py?key=${key}`;
+      p.src = url;
+      document.body.appendChild(p);
+    }, `{{host}} -> ${host} portal`);
+  }
+
+  create_test("{{host}}:{{ports[https][0]}}", {
+    "site": "same-origin",
+    "user": "",
+    "mode": "navigate",
+    "dest": "iframe"
+  });
+
+  create_test("{{hosts[][www]}}:{{ports[https][0]}}", {
+    "site": "same-site",
+    "user": "",
+    "mode": "navigate",
+    "dest": "iframe"
+  });
+
+  create_test("{{hosts[alt][www]}}:{{ports[https][0]}}", {
+    "site": "cross-site",
+    "user": "",
+    "mode": "navigate",
+    "dest": "iframe"
+  });
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/preload.https.sub.html b/testing/web-platform/tests/fetch/metadata/preload.https.sub.html
new file mode 100644
index 0000000000..29042a8547
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/preload.https.sub.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<meta name="timeout" content="long">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body></body>
+<script>
+  test(t => {
+    assert_true(document.createElement('link').relList.supports('preload'));
+  }, "Browser supports preload.");
+
+  function create_test(host, as, expected) {
+    async_test(t => {
+      let nonce = token();
+      let key = as + nonce;
+
+      let e = document.createElement('link');
+      e.rel = "preload";
+      e.href = `https://${host}/fetch/metadata/resources/record-header.py?file=${key}`;
+      e.setAttribute("crossorigin", "crossorigin");
+      if (as !== undefined) {
+        e.setAttribute("as", as);
+      }
+      e.onload = e.onerror = t.step_func(e => {
+        fetch("/fetch/metadata/resources/record-header.py?retrieve=true&file=" + key)
+          .then(t.step_func(response => response.text()))
+          .then(t.step_func_done(text => assert_header_equals(text, expected, `preload ${as} ${host}`)))
+          .catch(t.unreached_func());
+      });
+
+      document.head.appendChild(e);
+    }, `<link rel='preload' as='${as}' href='https://${host}/...'>`);
+  }
+
+  let as_tests = [
+    [ "fetch", "empty" ],
+    [ "font", "font" ],
+    [ "image", "image" ],
+    [ "script", "script" ],
+    [ "style", "style" ],
+    [ "track", "track" ],
+  ];
+
+  as_tests.forEach(item => {
+    create_test("{{host}}:{{ports[https][0]}}", item[0], {"site":"same-origin", "user":"", "mode": "cors", "dest": item[1]});
+    create_test("{{hosts[][www]}}:{{ports[https][0]}}", item[0], {"site":"same-site", "user":"", "mode": "cors", "dest": item[1]});
+    create_test("{{hosts[alt][www]}}:{{ports[https][0]}}", item[0], {"site":"cross-site", "user":"", "mode": "cors", "dest": item[1]});
+  });
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/redirect/multiple-redirect-https-downgrade-upgrade.sub.html b/testing/web-platform/tests/fetch/metadata/redirect/multiple-redirect-https-downgrade-upgrade.sub.html
new file mode 100644
index 0000000000..0f8f320016
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/redirect/multiple-redirect-https-downgrade-upgrade.sub.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/fetch/metadata/resources/redirectTestHelper.sub.js></script>
+<script src=/common/security-features/resources/common.sub.js></script>
+<script src=/common/utils.js></script>
+<body>
+<script>
+  let nonce = token();
+  let expected = {"site": "cross-site", "user": "", "mode": "cors", "dest": "font"};
+
+  // Validate various scenarios handle a request that redirects from https => http => https
+  // correctly and avoids disclosure of any Sec- headers.
+  RunCommonRedirectTests("Https downgrade-upgrade", MultipleRedirectTo, expected);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fetch/metadata/redirect/redirect-http-upgrade.sub.html b/testing/web-platform/tests/fetch/metadata/redirect/redirect-http-upgrade.sub.html
new file mode 100644
index 0000000000..fa765b66d0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/redirect/redirect-http-upgrade.sub.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/fetch/metadata/resources/redirectTestHelper.sub.js></script>
+<script src=/common/security-features/resources/common.sub.js></script>
+<script src=/common/utils.js></script>
+<body>
+<script>
+  let nonce = token();
+  let expected = { "site": "cross-site", "user": "", "mode": "cors", "dest": "font" };
+
+  // Validate various scenarios handle a request that redirects from http => https correctly and add the proper Sec- headers.
+  RunCommonRedirectTests("Http upgrade", upgradeRedirectTo, expected);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fetch/metadata/redirect/redirect-https-downgrade.sub.html b/testing/web-platform/tests/fetch/metadata/redirect/redirect-https-downgrade.sub.html
new file mode 100644
index 0000000000..4e5a48e6f6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/redirect/redirect-https-downgrade.sub.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/fetch/metadata/resources/redirectTestHelper.sub.js></script>
+<script src=/common/security-features/resources/common.sub.js></script>
+<script src=/common/utils.js></script>
+<body>
+  <script>
+  let nonce = token();
+  let expected = { "site": "", "user": "", "mode": "", "dest": "" };
+
+  // Validate various scenarios handle a request that redirects from https => http correctly and avoids disclosure of any Sec- headers.
+  RunCommonRedirectTests("Https downgrade", downgradeRedirectTo, expected);
+</script>
+</body>
diff --git a/testing/web-platform/tests/fetch/metadata/report.https.sub.html b/testing/web-platform/tests/fetch/metadata/report.https.sub.html
new file mode 100644
index 0000000000..b65f7c0a24
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/report.https.sub.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script>
+  setup({ explicit_done: true });
+  function generate_test(expected, name) {
+    async_test(t => {
+      t.step_timeout(_ => {
+        return validate_expectations("report-" + name, expected, name + " report")
+            .then(_ => t.done());
+      }, 1000);
+    }, name + " report");
+  }
+
+  let counter = 0;
+  document.addEventListener("securitypolicyviolation", (e) => {
+    counter++;
+    if (counter == 3) {
+      generate_test({"site":"same-origin", "user":"", "mode": "no-cors", "dest": "report"}, "same-origin");
+      generate_test({"site":"same-site", "user":"", "mode": "no-cors", "dest": "report"}, "same-site");
+      generate_test({"site":"cross-site", "user":"", "mode": "no-cors", "dest": "report"}, "cross-site");
+
+      done();
+    }
+  });
+</script>
+
+<!-- The hostname here is unimportant, so long as it doesn't match 'self'. -->
+<link id="style" href="https://{{hosts[alt][élève]}}:{{ports[https][0]}}/css/support/a-green.css" rel="stylesheet">
+
+<body></body>
diff --git a/testing/web-platform/tests/fetch/metadata/report.https.sub.html.sub.headers b/testing/web-platform/tests/fetch/metadata/report.https.sub.html.sub.headers
new file mode 100644
index 0000000000..1ec5df78f3
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/report.https.sub.html.sub.headers
@@ -0,0 +1,3 @@
+Content-Security-Policy: style-src 'self' 'unsafe-inline'; report-uri /fetch/metadata/resources/record-header.py?file=report-same-origin
+Content-Security-Policy: style-src 'self' 'unsafe-inline'; report-uri https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=report-same-site
+Content-Security-Policy: style-src 'self' 'unsafe-inline'; report-uri https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=report-cross-site
diff --git a/testing/web-platform/tests/fetch/metadata/resources/appcache-iframe.sub.html b/testing/web-platform/tests/fetch/metadata/resources/appcache-iframe.sub.html
new file mode 100644
index 0000000000..cea9a4feae
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/appcache-iframe.sub.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html lang="en" manifest="{{GET[manifest]}}">
+<script>
+if (!window.applicationCache) {
+  parent.postMessage('application cache not supported');
+} else {
+  applicationCache.onnoupdate =
+    applicationCache.ondownloading =
+    applicationCache.onobsolete =
+    applicationCache.onerror = function() {
+      parent.postMessage('okay');
+    };
+}
+</script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/resources/dedicatedWorker.js b/testing/web-platform/tests/fetch/metadata/resources/dedicatedWorker.js
new file mode 100644
index 0000000000..18626d3d84
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/dedicatedWorker.js
@@ -0,0 +1 @@
+self.postMessage("Loaded");
diff --git a/testing/web-platform/tests/fetch/metadata/resources/echo-as-json.py b/testing/web-platform/tests/fetch/metadata/resources/echo-as-json.py
new file mode 100644
index 0000000000..44f68e8fe9
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/echo-as-json.py
@@ -0,0 +1,29 @@
+import json
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+    headers = [(b"Content-Type", b"application/json"),
+               (b"Access-Control-Allow-Credentials", b"true")]
+
+    if b"origin" in request.headers:
+        headers.append((b"Access-Control-Allow-Origin", request.headers[b"origin"]))
+
+    body = u""
+
+    # If we're in a preflight, verify that `Sec-Fetch-Mode` is `cors`.
+    if request.method == u'OPTIONS':
+        if request.headers.get(b"sec-fetch-mode") != b"cors":
+            return (403, b"Failed"), [], body
+
+        headers.append((b"Access-Control-Allow-Methods", b"*"))
+        headers.append((b"Access-Control-Allow-Headers", b"*"))
+    else:
+        body = json.dumps({
+            u"dest": isomorphic_decode(request.headers.get(b"sec-fetch-dest", b"")),
+            u"mode": isomorphic_decode(request.headers.get(b"sec-fetch-mode", b"")),
+            u"site": isomorphic_decode(request.headers.get(b"sec-fetch-site", b"")),
+            u"user": isomorphic_decode(request.headers.get(b"sec-fetch-user", b"")),
+            })
+
+    return headers, body
diff --git a/testing/web-platform/tests/fetch/metadata/resources/echo-as-script.py b/testing/web-platform/tests/fetch/metadata/resources/echo-as-script.py
new file mode 100644
index 0000000000..1e7bc91184
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/echo-as-script.py
@@ -0,0 +1,14 @@
+import json
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+    headers = [(b"Content-Type", b"text/javascript")]
+    body = u"var header = %s;" % json.dumps({
+        u"dest": isomorphic_decode(request.headers.get(b"sec-fetch-dest", b"")),
+        u"mode": isomorphic_decode(request.headers.get(b"sec-fetch-mode", b"")),
+        u"site": isomorphic_decode(request.headers.get(b"sec-fetch-site", b"")),
+        u"user": isomorphic_decode(request.headers.get(b"sec-fetch-user", b"")),
+        })
+
+    return headers, body
diff --git a/testing/web-platform/tests/fetch/metadata/resources/es-module.sub.js b/testing/web-platform/tests/fetch/metadata/resources/es-module.sub.js
new file mode 100644
index 0000000000..f9668a3dc6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/es-module.sub.js
@@ -0,0 +1 @@
+import '{{GET[moduleId]}}';
diff --git a/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--fallback--sw.js b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--fallback--sw.js
new file mode 100644
index 0000000000..09858b2663
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--fallback--sw.js
@@ -0,0 +1,3 @@
+self.addEventListener('fetch', function(event) {
+    // Empty event handler - will fallback to the network.
+});
diff --git a/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--respondWith--sw.js b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--respondWith--sw.js
new file mode 100644
index 0000000000..8bf8d8f221
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker--respondWith--sw.js
@@ -0,0 +1,3 @@
+self.addEventListener('fetch', function(event) {
+    event.respondWith(fetch(event.request));
+});
diff --git a/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker-frame.html b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker-frame.html
new file mode 100644
index 0000000000..9879802500
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/fetch-via-serviceworker-frame.html
@@ -0,0 +1,3 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Page Title</title>
diff --git a/testing/web-platform/tests/fetch/metadata/resources/header-link.py b/testing/web-platform/tests/fetch/metadata/resources/header-link.py
new file mode 100644
index 0000000000..de891163a3
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/header-link.py
@@ -0,0 +1,15 @@
+def main(request, response):
+    """
+    Respond with a blank HTML document and a `Link` header which describes
+    a link relation specified by the requests `location` and `rel` query string
+    parameters
+    """
+    headers = [
+        (b'Content-Type', b'text/html'),
+        (
+          b'Link',
+          b'<' + request.GET.first(b'location') + b'>; rel=' + request.GET.first(b'rel')
+        )
+    ]
+    return (200, headers, b'')
+
diff --git a/testing/web-platform/tests/fetch/metadata/resources/helper.js b/testing/web-platform/tests/fetch/metadata/resources/helper.js
new file mode 100644
index 0000000000..725f9a7e43
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/helper.js
@@ -0,0 +1,42 @@
+function validate_expectations(key, expected, tag) {
+  return fetch("/fetch/metadata/resources/record-header.py?retrieve=true&file=" + key)
+    .then(response => response.text())
+    .then(text => {
+      assert_not_equals(text, "No header has been recorded");
+      let value = JSON.parse(text);
+      test(t => assert_equals(value.dest, expected.dest), `${tag}: sec-fetch-dest`);
+      test(t => assert_equals(value.mode, expected.mode), `${tag}: sec-fetch-mode`);
+      test(t => assert_equals(value.site, expected.site), `${tag}: sec-fetch-site`);
+      test(t => assert_equals(value.user, expected.user), `${tag}: sec-fetch-user`);
+    });
+}
+
+function validate_expectations_custom_url(url, header, expected, tag) {
+  return fetch(url, header)
+    .then(response => response.text())
+    .then(text => {
+      assert_not_equals(text, "No header has been recorded");
+      let value = JSON.parse(text);
+      test(t => assert_equals(value.dest, expected.dest), `${tag}: sec-fetch-dest`);
+      test(t => assert_equals(value.mode, expected.mode), `${tag}: sec-fetch-mode`);
+      test(t => assert_equals(value.site, expected.site), `${tag}: sec-fetch-site`);
+      test(t => assert_equals(value.user, expected.user), `${tag}: sec-fetch-user`);
+    });
+}
+
+/**
+ * @param {object} value
+ * @param {object} expected
+ * @param {string} tag
+ **/
+function assert_header_equals(value, expected, tag) {
+  if (typeof(value) === "string"){
+    assert_not_equals(value, "No header has been recorded");
+    value = JSON.parse(value);
+  }
+
+  test(t => assert_equals(value.dest, expected.dest), `${tag}: sec-fetch-dest`);
+  test(t => assert_equals(value.mode, expected.mode), `${tag}: sec-fetch-mode`);
+  test(t => assert_equals(value.site, expected.site), `${tag}: sec-fetch-site`);
+  test(t => assert_equals(value.user, expected.user), `${tag}: sec-fetch-user`);
+}
diff --git a/testing/web-platform/tests/fetch/metadata/resources/helper.sub.js b/testing/web-platform/tests/fetch/metadata/resources/helper.sub.js
new file mode 100644
index 0000000000..fd179fe6f2
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/helper.sub.js
@@ -0,0 +1,67 @@
+'use strict';
+
+/**
+ * Construct a URL which, when followed, will trigger redirection through zero
+ * or more specified origins and ultimately resolve in the Python handler
+ * `record-headers.py`.
+ *
+ * @param {string} key - the WPT server "stash" name where the request's
+ *                       headers should be stored
+ * @param {string[]} [origins] - zero or more origin names through which the
+ *                               request should pass; see the function
+ *                               implementation for a completel list of names
+ *                               and corresponding origins; If specified, the
+ *                               final origin will be used to access the
+ *                               `record-headers.py` hander.
+ * @param {object} [params] - a collection of key-value pairs to include as
+ *                            URL "search" parameters in the final request to
+ *                            `record-headers.py`
+ *
+ * @returns {string} an absolute URL
+ */
+function makeRequestURL(key, origins, params) {
+    const byName = {
+        httpOrigin: 'http://{{host}}:{{ports[http][0]}}',
+        httpSameSite: 'http://{{hosts[][www]}}:{{ports[http][0]}}',
+        httpCrossSite: 'http://{{hosts[alt][]}}:{{ports[http][0]}}',
+        httpsOrigin: 'https://{{host}}:{{ports[https][0]}}',
+        httpsSameSite: 'https://{{hosts[][www]}}:{{ports[https][0]}}',
+        httpsCrossSite: 'https://{{hosts[alt][]}}:{{ports[https][0]}}'
+    };
+    const redirectPath = '/fetch/api/resources/redirect.py?location=';
+    const path = '/fetch/metadata/resources/record-headers.py?key=' + key;
+
+    let requestUrl = path;
+    if (params) {
+      requestUrl += '&' + new URLSearchParams(params).toString();
+    }
+
+    if (origins && origins.length) {
+      requestUrl = byName[origins.pop()] + requestUrl;
+
+      while (origins.length) {
+        requestUrl = byName[origins.pop()] + redirectPath +
+          encodeURIComponent(requestUrl);
+      }
+    } else {
+      requestUrl = byName.httpsOrigin + requestUrl;
+    }
+
+    return requestUrl;
+}
+
+function retrieve(key, options) {
+  return fetch('/fetch/metadata/resources/record-headers.py?retrieve&key=' + key)
+    .then((response) => {
+      if (response.status === 204 && options && options.poll) {
+        return new Promise((resolve) => setTimeout(resolve, 300))
+          .then(() => retrieve(key, options));
+      }
+
+      if (response.status !== 200) {
+        throw new Error('Failed to query for recorded headers.');
+      }
+
+      return response.text().then((text) => JSON.parse(text));
+    });
+}
diff --git a/testing/web-platform/tests/fetch/metadata/resources/message-opener.html b/testing/web-platform/tests/fetch/metadata/resources/message-opener.html
new file mode 100644
index 0000000000..eb2af7b250
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/message-opener.html
@@ -0,0 +1,17 @@
+<script>
+/**
+ * Send a message to the opening browsing context when the document is
+ * "completely loaded" (a condition which occurs immediately after the `load`
+ * and `pageshow` events are fired).
+ * https://html.spec.whatwg.org/multipage/parsing.html#the-end
+ */
+'use strict';
+
+// The `pageshow` event is used instead of the `load` event because this
+// document may itself be accessed via history traversal. In such cases, the
+// browser may choose to reuse a cached document and therefore fire no
+// additional `load` events.
+addEventListener('pageshow', () => {
+  setTimeout(() => opener.postMessage(null, '*'), 0);
+});
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/resources/post-to-owner.py b/testing/web-platform/tests/fetch/metadata/resources/post-to-owner.py
new file mode 100644
index 0000000000..256dd6e49d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/post-to-owner.py
@@ -0,0 +1,36 @@
+import json
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+    headers = [
+        (b"Content-Type", b"text/html"),
+        (b"Cache-Control", b"no-cache, no-store, must-revalidate")
+    ]
+    key = request.GET.first(b"key", None)
+
+    # We serialize the key into JSON, so have to decode it first.
+    if key is not None:
+      key = key.decode('utf-8')
+
+    body = u"""
+        <!DOCTYPE html>
+        <script src="/portals/resources/stash-utils.sub.js"></script>
+        <script>
+            var data = %s;
+            if (window.opener)
+                window.opener.postMessage(data, "*");
+            if (window.top != window)
+                window.top.postMessage(data, "*");
+
+            const key = %s;
+            if (key)
+                StashUtils.putValue(key, data);
+        </script>
+    """ % (json.dumps({
+        u"dest": isomorphic_decode(request.headers.get(b"sec-fetch-dest", b"")),
+        u"mode": isomorphic_decode(request.headers.get(b"sec-fetch-mode", b"")),
+        u"site": isomorphic_decode(request.headers.get(b"sec-fetch-site", b"")),
+        u"user": isomorphic_decode(request.headers.get(b"sec-fetch-user", b"")),
+        }), json.dumps(key))
+    return headers, body
diff --git a/testing/web-platform/tests/fetch/metadata/resources/record-header.py b/testing/web-platform/tests/fetch/metadata/resources/record-header.py
new file mode 100644
index 0000000000..29ff2ed798
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/record-header.py
@@ -0,0 +1,145 @@
+import os
+import hashlib
+import json
+
+from wptserve.utils import isomorphic_decode
+
+def main(request, response):
+  ## Get the query parameter (key) from URL ##
+  ## Tests will record POST requests (CSP Report) and GET (rest) ##
+  if request.GET:
+    key = request.GET[b'file']
+  elif request.POST:
+    key = request.POST[b'file']
+
+  ## Convert the key from String to UUID valid String ##
+  testId = hashlib.md5(key).hexdigest()
+
+  ## Handle the header retrieval request ##
+  if b'retrieve' in request.GET:
+    response.writer.write_status(200)
+    response.writer.write_header(b"Connection", b"close")
+    response.writer.end_headers()
+    try:
+      header_value = request.server.stash.take(testId)
+      response.writer.write(header_value)
+    except (KeyError, ValueError) as e:
+      response.writer.write(u"No header has been recorded")
+      pass
+
+    response.close_connection = True
+
+  ## Record incoming fetch metadata header value
+  else:
+    try:
+      ## Return a serialized JSON object with one member per header. If the ##
+      ## header isn't present, the member will contain an empty string.     ##
+      header = json.dumps({
+        u"dest": isomorphic_decode(request.headers.get(b"sec-fetch-dest", b"")),
+        u"mode": isomorphic_decode(request.headers.get(b"sec-fetch-mode", b"")),
+        u"site": isomorphic_decode(request.headers.get(b"sec-fetch-site", b"")),
+        u"user": isomorphic_decode(request.headers.get(b"sec-fetch-user", b"")),
+      })
+      request.server.stash.put(testId, header)
+    except KeyError:
+      ## The header is already recorded or it doesn't exist
+      pass
+
+    ## Prevent the browser from caching returned responses and allow CORS ##
+    response.headers.set(b"Access-Control-Allow-Origin", b"*")
+    response.headers.set(b"Cache-Control", b"no-cache, no-store, must-revalidate")
+    response.headers.set(b"Pragma", b"no-cache")
+    response.headers.set(b"Expires", b"0")
+
+    ## Add a valid ServiceWorker Content-Type ##
+    if key.startswith(b"serviceworker"):
+      response.headers.set(b"Content-Type", b"application/javascript")
+
+    ## Add a valid image Content-Type ##
+    if key.startswith(b"image"):
+      response.headers.set(b"Content-Type", b"image/png")
+      file = open(os.path.join(request.doc_root, u"media", u"1x1-green.png"), u"rb")
+      image = file.read()
+      file.close()
+      return image
+
+    ## Return a valid .vtt content for the <track> tag ##
+    if key.startswith(b"track"):
+      return b"WEBVTT"
+
+    ## Return a valid SharedWorker ##
+    if key.startswith(b"sharedworker"):
+      response.headers.set(b"Content-Type", b"application/javascript")
+      file = open(os.path.join(request.doc_root, u"fetch", u"metadata",
+                               u"resources", u"sharedWorker.js"), u"rb")
+      shared_worker = file.read()
+      file.close()
+      return shared_worker
+
+    ## Return a valid font content and Content-Type ##
+    if key.startswith(b"font"):
+      response.headers.set(b"Content-Type", b"application/x-font-ttf")
+      file = open(os.path.join(request.doc_root, u"fonts", u"Ahem.ttf"), u"rb")
+      font = file.read()
+      file.close()
+      return font
+
+    ## Return a valid audio content and Content-Type ##
+    if key.startswith(b"audio"):
+      response.headers.set(b"Content-Type", b"audio/mpeg")
+      file = open(os.path.join(request.doc_root, u"media", u"sound_5.mp3"), u"rb")
+      audio = file.read()
+      file.close()
+      return audio
+
+    ## Return a valid video content and Content-Type ##
+    if key.startswith(b"video"):
+      response.headers.set(b"Content-Type", b"video/mp4")
+      file = open(os.path.join(request.doc_root, u"media", u"A4.mp4"), u"rb")
+      video = file.read()
+      file.close()
+      return video
+
+    ## Return valid style content and Content-Type ##
+    if key.startswith(b"style"):
+      response.headers.set(b"Content-Type", b"text/css")
+      return b"div { }"
+
+    ## Return a valid embed/object content and Content-Type ##
+    if key.startswith(b"embed") or key.startswith(b"object"):
+      response.headers.set(b"Content-Type", b"text/html")
+      return b"<html>EMBED!</html>"
+
+    ## Return a valid image content and Content-Type for redirect requests ##
+    if key.startswith(b"redirect"):
+      response.headers.set(b"Content-Type", b"image/jpeg")
+      file = open(os.path.join(request.doc_root, u"media", u"1x1-green.png"), u"rb")
+      image = file.read()
+      file.close()
+      return image
+
+    ## Return a valid dedicated worker
+    if key.startswith(b"worker"):
+      response.headers.set(b"Content-Type", b"application/javascript")
+      return b"self.postMessage('loaded');"
+
+    ## Return a valid worklet
+    if key.startswith(b"worklet"):
+      response.headers.set(b"Content-Type", b"application/javascript")
+      return b""
+
+    ## Return a valid XSLT
+    if key.startswith(b"xslt"):
+      response.headers.set(b"Content-Type", b"text/xsl")
+      return b"""<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
+  <xsl:template match="@*|node()">
+    <xsl:copy>
+      <xsl:apply-templates select="@*|node()"/>
+    </xsl:copy>
+  </xsl:template>
+</xsl:stylesheet>"""
+
+    if key.startswith(b"script"):
+      response.headers.set(b"Content-Type", b"application/javascript")
+      return b"void 0;"
diff --git a/testing/web-platform/tests/fetch/metadata/resources/record-headers.py b/testing/web-platform/tests/fetch/metadata/resources/record-headers.py
new file mode 100644
index 0000000000..0362fe228c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/record-headers.py
@@ -0,0 +1,73 @@
+import os
+import uuid
+import hashlib
+import time
+import json
+
+
+def bytes_to_strings(d):
+  # Recursively convert bytes to strings in `d`.
+  if not isinstance(d, dict):
+    if isinstance(d, (tuple,list,set)):
+      v = [bytes_to_strings(x) for x in d]
+      return v
+    else:
+      if isinstance(d, bytes):
+        d = d.decode()
+      return d
+
+  result = {}
+  for k,v in d.items():
+    if isinstance(k, bytes):
+      k = k.decode()
+    if isinstance(v, dict):
+      v = bytes_to_strings(v)
+    elif isinstance(v, (tuple,list,set)):
+      v = [bytes_to_strings(x) for x in v]
+    elif isinstance(v, bytes):
+      v = v.decode()
+    result[k] = v
+  return result
+
+
+def main(request, response):
+  # This condition avoids false positives from CORS preflight checks, where the
+  # request under test may be followed immediately by a request to the same URL
+  # using a different HTTP method.
+  if b'requireOPTIONS' in request.GET and request.method != b'OPTIONS':
+      return
+
+  if b'key' in request.GET:
+    key = request.GET[b'key']
+  elif b'key' in request.POST:
+    key = request.POST[b'key']
+
+  ## Convert the key from String to UUID valid String ##
+  testId = hashlib.md5(key).hexdigest()
+
+  ## Handle the header retrieval request ##
+  if b'retrieve' in request.GET:
+    recorded_headers = request.server.stash.take(testId)
+
+    if recorded_headers is None:
+      return (204, [], b'')
+
+    return (200, [], recorded_headers)
+
+  ## Record incoming fetch metadata header value
+  else:
+    try:
+      request.server.stash.put(testId, json.dumps(bytes_to_strings(request.headers)))
+    except KeyError:
+      ## The header is already recorded or it doesn't exist
+      pass
+
+    ## Prevent the browser from caching returned responses and allow CORS ##
+    response.headers.set(b"Access-Control-Allow-Origin", b"*")
+    response.headers.set(b"Cache-Control", b"no-cache, no-store, must-revalidate")
+    response.headers.set(b"Pragma", b"no-cache")
+    response.headers.set(b"Expires", b"0")
+    if b"mime" in request.GET:
+        response.headers.set(b"Content-Type", request.GET.first(b"mime"))
+
+    return request.GET.first(b"body", request.POST.first(b"body", b""))
diff --git a/testing/web-platform/tests/fetch/metadata/resources/redirectTestHelper.sub.js b/testing/web-platform/tests/fetch/metadata/resources/redirectTestHelper.sub.js
new file mode 100644
index 0000000000..1bfbbae70c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/redirectTestHelper.sub.js
@@ -0,0 +1,167 @@
+function createVideoElement() {
+  let el = document.createElement('video');
+  el.src = '/media/movie_5.mp4';
+  el.setAttribute('controls', '');
+  el.setAttribute('crossorigin', '');
+  return el;
+}
+
+function createTrack() {
+  let el = document.createElement('track');
+  el.setAttribute('default', '');
+  el.setAttribute('kind', 'captions');
+  el.setAttribute('srclang', 'en');
+  return el;
+}
+
+let secureRedirectURL = 'https://{{host}}:{{ports[https][0]}}/fetch/api/resources/redirect.py?location=';
+let insecureRedirectURL = 'http://{{host}}:{{ports[http][0]}}/fetch/api/resources/redirect.py?location=';
+let secureTestURL = 'https://{{host}}:{{ports[https][0]}}/fetch/metadata/';
+let insecureTestURL = 'http://{{host}}:{{ports[http][0]}}/fetch/metadata/';
+
+// Helper to craft an URL that will go from HTTPS => HTTP => HTTPS to
+// simulate us downgrading then upgrading again during the same redirect chain.
+function MultipleRedirectTo(partialPath) {
+  let finalURL = insecureRedirectURL + encodeURIComponent(secureTestURL + partialPath);
+  return secureRedirectURL + encodeURIComponent(finalURL);
+}
+
+// Helper to craft an URL that will go from HTTP => HTTPS to simulate upgrading a
+// given request.
+function upgradeRedirectTo(partialPath) {
+  return insecureRedirectURL + encodeURIComponent(secureTestURL + partialPath);
+}
+
+// Helper to craft an URL that will go from HTTPS => HTTP to simulate downgrading a
+// given request.
+function downgradeRedirectTo(partialPath) {
+  return secureRedirectURL + encodeURIComponent(insecureTestURL + partialPath);
+}
+
+// Helper to run common redirect test cases that don't require special setup on
+// the test page itself.
+function RunCommonRedirectTests(testNamePrefix, urlHelperMethod, expectedResults) {
+  async_test(t => {
+    let testWindow = window.open(urlHelperMethod('resources/post-to-owner.py?top-level-navigation' + nonce));
+    t.add_cleanup(_ => testWindow.close());
+    window.addEventListener('message', t.step_func(e => {
+      if (e.source != testWindow) {
+        return;
+      }
+
+      let expectation = { ...expectedResults };
+      if (expectation['mode'] != '')
+        expectation['mode'] = 'navigate';
+      if (expectation['dest'] == 'font')
+        expectation['dest'] = 'document';
+      assert_header_equals(e.data, expectation, testNamePrefix + ' top level navigation');
+      t.done();
+    }));
+  }, testNamePrefix + ' top level navigation');
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = 'embed-https-redirect' + nonce;
+      let e = document.createElement('embed');
+      e.src = urlHelperMethod('resources/record-header.py?file=' + key);
+      e.onload = e => {
+        let expectation = { ...expectedResults };
+        if (expectation['mode'] != '')
+          expectation['mode'] = 'navigate';
+        if (expectation['dest'] == 'font')
+          expectation['dest'] = 'embed';
+        fetch('/fetch/metadata/resources/record-header.py?retrieve=true&file=' + key)
+          .then(response => response.text())
+          .then(t.step_func(text => assert_header_equals(text, expectation, testNamePrefix + ' embed')))
+          .then(resolve)
+          .catch(e => reject(e));
+      };
+      document.body.appendChild(e);
+    });
+  }, testNamePrefix + ' embed');
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = 'object-https-redirect' + nonce;
+      let e = document.createElement('object');
+      e.data = urlHelperMethod('resources/record-header.py?file=' + key);
+      e.onload = e => {
+        let expectation = { ...expectedResults };
+        if (expectation['mode'] != '')
+          expectation['mode'] = 'navigate';
+        if (expectation['dest'] == 'font')
+          expectation['dest'] = 'object';
+        fetch('/fetch/metadata/resources/record-header.py?retrieve=true&file=' + key)
+          .then(response => response.text())
+          .then(t.step_func(text => assert_header_equals(text, expectation, testNamePrefix + ' object')))
+          .then(resolve)
+          .catch(e => reject(e));
+      };
+      document.body.appendChild(e);
+    });
+  }, testNamePrefix + ' object');
+
+  if (document.createElement('link').relList.supports('preload')) {
+    async_test(t => {
+      let key = 'preload' + nonce;
+      let e = document.createElement('link');
+      e.rel = 'preload';
+      e.href = urlHelperMethod('resources/record-header.py?file=' + key);
+      e.setAttribute('as', 'track');
+      e.onload = e.onerror = t.step_func_done(e => {
+        let expectation = { ...expectedResults };
+        if (expectation['mode'] != '')
+          expectation['mode'] = 'cors';
+        fetch('/fetch/metadata/resources/record-header.py?retrieve=true&file=' + key)
+          .then(t.step_func(response => response.text()))
+          .then(t.step_func_done(text => assert_header_equals(text, expectation, testNamePrefix + ' preload')))
+          .catch(t.unreached_func());
+      });
+      document.head.appendChild(e);
+    }, testNamePrefix + ' preload');
+  }
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = 'style-https-redirect' + nonce;
+      let e = document.createElement('link');
+      e.rel = 'stylesheet';
+      e.href = urlHelperMethod('resources/record-header.py?file=' + key);
+      e.onload = e => {
+        let expectation = { ...expectedResults };
+        if (expectation['mode'] != '')
+          expectation['mode'] = 'no-cors';
+        if (expectation['dest'] == 'font')
+          expectation['dest'] = 'style';
+        fetch('/fetch/metadata/resources/record-header.py?retrieve=true&file=' + key)
+          .then(response => response.text())
+          .then(t.step_func(text => assert_header_equals(text, expectation, testNamePrefix + ' stylesheet')))
+          .then(resolve)
+          .catch(e => reject(e));
+      };
+      document.body.appendChild(e);
+    });
+  }, testNamePrefix + ' stylesheet');
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = 'track-https-redirect' + nonce;
+      let video = createVideoElement();
+      let el = createTrack();
+      el.src = urlHelperMethod('resources/record-header.py?file=' + key);
+      el.onload = t.step_func(_ => {
+        let expectation = { ...expectedResults };
+        if (expectation['mode'] != '')
+          expectation['mode'] = 'cors';
+        if (expectation['dest'] == 'font')
+          expectation['dest'] = 'track';
+        fetch('/fetch/metadata/resources/record-header.py?retrieve=true&file=' + key)
+          .then(response => response.text())
+          .then(t.step_func(text => assert_header_equals(text, expectation, testNamePrefix + ' track')))
+          .then(resolve);
+      });
+      video.appendChild(el);
+      document.body.appendChild(video);
+    });
+  }, testNamePrefix + ' track');
+}
diff --git a/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors-frame.html b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors-frame.html
new file mode 100644
index 0000000000..9879802500
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors-frame.html
@@ -0,0 +1,3 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Page Title</title>
diff --git a/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors.sw.js b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors.sw.js
new file mode 100644
index 0000000000..36c55a7786
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors.sw.js
@@ -0,0 +1,14 @@
+addEventListener("fetch", event => {
+  event.waitUntil(async function () {
+    if (!event.clientId) return;
+    const client = await clients.get(event.clientId);
+    if (!client) return;
+
+    client.postMessage({
+      "dest": event.request.headers.get("sec-fetch-dest"),
+      "mode": event.request.headers.get("sec-fetch-mode"),
+      "site": event.request.headers.get("sec-fetch-site"),
+      "user": event.request.headers.get("sec-fetch-user")
+    });
+  }());
+});
diff --git a/testing/web-platform/tests/fetch/metadata/resources/sharedWorker.js b/testing/web-platform/tests/fetch/metadata/resources/sharedWorker.js
new file mode 100644
index 0000000000..5eb89cb4f6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/sharedWorker.js
@@ -0,0 +1,9 @@
+onconnect = function(e) {
+  var port = e.ports[0];
+
+  port.addEventListener('message', function(e) {
+    port.postMessage("Ready");
+  });
+
+  port.start();
+}
diff --git a/testing/web-platform/tests/fetch/metadata/resources/unload-with-beacon.html b/testing/web-platform/tests/fetch/metadata/resources/unload-with-beacon.html
new file mode 100644
index 0000000000..b00c9a5776
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/unload-with-beacon.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<script>
+  // When told, register an unload handler that will trigger a beacon to the
+  // URL given by the sender of the message.
+  window.addEventListener('message', e => {
+      var url = e.data;
+      window.addEventListener('unload', () => {
+          navigator.sendBeacon(url, 'blah');
+      });
+      window.parent.postMessage('navigate-away', '*');
+  });
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/resources/xslt-test.sub.xml b/testing/web-platform/tests/fetch/metadata/resources/xslt-test.sub.xml
new file mode 100644
index 0000000000..acb478ab64
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/xslt-test.sub.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<?xml-stylesheet href="https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=xslt-same-origin{{GET[token]}}" type="text/xsl" ?>
+<!-- Only testing same-origin XSLT because same-site and cross-site XSLT is blocked. -->
+
+<!-- postMessage parent back when the resources are loaded -->
+<script xmlns="http://www.w3.org/1999/xhtml"><![CDATA[
+  setTimeout(function(){
+    if (window.opener)
+        window.opener.postMessage("", "*");
+    if (window.top != window)
+        window.top.postMessage("", "*");}, 100);
+]]></script>
diff --git a/testing/web-platform/tests/fetch/metadata/serviceworker-accessors.https.sub.html b/testing/web-platform/tests/fetch/metadata/serviceworker-accessors.https.sub.html
new file mode 100644
index 0000000000..03a8321d4c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/serviceworker-accessors.https.sub.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<!--
+  This test verifies that Fetch Metadata headers are not exposed to Service
+  Workers via the request's `headers` accessor.
+-->
+<meta charset="utf-8"/>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/service-workers/service-worker/resources/test-helpers.sub.js></script>
+<script src=/common/utils.js></script>
+<script>
+  const SCOPE = 'resources/serviceworker-accessors-frame.html';
+  const SCRIPT = 'resources/serviceworker-accessors.sw.js';
+
+  function assert_headers_not_seen_in_service_worker(frame) {
+    return new Promise((resolve, reject) => {
+      frame.contentWindow.fetch(SCOPE, {mode:'no-cors'});
+      frame.contentWindow.navigator.serviceWorker.addEventListener('message', e => {
+        assert_header_equals(e.data, {
+          "dest": null,
+          "mode": null,
+          "site": null,
+          "user": null
+        });
+        resolve();
+      });
+    });
+  }
+
+  promise_test(async function(t) {
+    const reg = await service_worker_unregister_and_register(t, SCRIPT, SCOPE);
+
+    t.add_cleanup(async () => {
+      if (reg)
+        await reg.unregister();
+    });
+
+    await wait_for_state(t, reg.installing, 'activated');
+
+    const frame = await with_iframe(SCOPE);
+    t.add_cleanup(async () => {
+      if (frame)
+        frame.remove();
+    });
+
+    // Trigger a fetch that will go through the service worker, and validate
+    // the visible headers.
+    await assert_headers_not_seen_in_service_worker(frame);
+  }, 'Sec-Fetch headers in Service Worker fetch handler.');
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/sharedworker.https.sub.html b/testing/web-platform/tests/fetch/metadata/sharedworker.https.sub.html
new file mode 100644
index 0000000000..4df858208a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/sharedworker.https.sub.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script>
+  let nonce = token();
+  let key = "sharedworker-same-origin" + nonce;
+
+  // TESTS //
+  if (window.Worker) {
+
+      //  Same-Origin test
+      var sharedWorker = new SharedWorker('/fetch/metadata/resources/record-header.py?file=' + key);
+      sharedWorker.port.start();
+
+      sharedWorker.onerror = function(){
+        test_same_origin();
+      }
+      sharedWorker.port.onmessage = function(e) {
+        test_same_origin();
+      }
+      sharedWorker.port.postMessage("Ready");
+    }
+
+  function test_same_origin(){
+    promise_test(t => {
+      return new Promise((resolve, reject) => {
+        let expected = {"site":"same-origin", "user":"", "mode": "same-origin", "dest": "sharedworker"};
+
+        validate_expectations(key, expected)
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      })
+    }, "Same-Origin sharedworker")
+  }
+</script>
+<body></body>
diff --git a/testing/web-platform/tests/fetch/metadata/style.https.sub.html b/testing/web-platform/tests/fetch/metadata/style.https.sub.html
new file mode 100644
index 0000000000..a30d81d70d
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/style.https.sub.html
@@ -0,0 +1,86 @@
+<!DOCTYPE html>
+<html>
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body></body>
+<script>
+  let nonce = token();
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "style-same-origin" + nonce;
+
+      let e = document.createElement('link');
+      e.rel = "stylesheet";
+      e.href = "https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"same-origin", "user":"", "mode": "no-cors", "dest": "style"};
+        validate_expectations(key, expected, "Same-Origin style")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Same-Origin style");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "style-same-site" + nonce;
+
+      let e = document.createElement('link');
+      e.rel = "stylesheet";
+      e.href = "https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"same-site", "user":"", "mode": "no-cors", "dest": "style"};
+        validate_expectations(key, expected, "Same-Site style")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Same-Site style");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "style-cross-site" + nonce;
+
+      let e = document.createElement('link');
+      e.rel = "stylesheet";
+      e.href = "https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.onload = e => {
+        let expected = {"site":"cross-site", "user":"", "mode": "no-cors", "dest": "style"};
+        validate_expectations(key, expected, "Cross-Site style")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Cross-Site style");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "style-same-origin-cors" + nonce;
+
+      let e = document.createElement('link');
+      e.rel = "stylesheet";
+      e.href = "https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      e.crossOrigin = "anonymous";
+      e.onload = e => {
+        let expected = {"site":"same-origin", "user":"", "mode": "cors", "dest": "style"};
+        validate_expectations(key, expected, "Same-Origin, cors style")
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+
+      document.body.appendChild(e);
+    })
+  }, "Same-Origin, cors style");
+</script>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/tools/README.md b/testing/web-platform/tests/fetch/metadata/tools/README.md
new file mode 100644
index 0000000000..1c3bac2be5
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/README.md
@@ -0,0 +1,126 @@
+# Fetch Metadata test generation framework
+
+This directory defines a command-line tool for procedurally generating WPT
+tests.
+
+## Motivation
+
+Many features of the web platform involve the browser making one or more HTTP
+requests to remote servers. Only some aspects of these requests are specified
+within the standard that defines the relevant feature. Other aspects are
+specified by external standards which span the entire platform (e.g. [Fetch
+Metadata Request Headers](https://w3c.github.io/webappsec-fetch-metadata/)).
+
+This state of affairs makes it difficult to maintain test coverage for two
+reasons:
+
+- When a new feature introduces a new kind of web request, it must be verified
+  to integrate with every cross-cutting standard.
+- When a new cross-cutting standard is introduced, it must be verified to
+  integrate with every kind of web request.
+
+The tool in this directory attempts to reduce this tension. It allows
+maintainers to express instructions for making web requests in an abstract
+sense. These generic instructions can be reused by to produce a different suite
+of tests for each cross-cutting feature.
+
+When a new kind of request is proposed, a single generic template can be
+defined here. This will provide the maintainers of all cross-cutting features
+with clear instruction on how to extend their test suite with the new feature.
+
+Similarly, when a new cross-cutting feature is proposed, the authors can use
+this tool to build a test suite which spans the entire platform.
+
+## Build script
+
+To generate the Fetch Metadata tests, run `./wpt update-built --include fetch`
+in the root of the repository.
+
+## Configuration
+
+The test generation tool requires a YAML-formatted configuration file as its
+input. The file should define a dictionary with the following keys:
+
+- `templates` - a string describing the filesystem path from which template
+  files should be loaded
+- `output_directory` - a string describing the filesystem path where the
+  generated test files should be written
+- `cases` - a list of dictionaries describing how the test templates should be
+  expanded with individual subtests; each dictionary should have the following
+  keys:
+  - `all_subtests` - properties which should be defined for every expansion
+  - `common_axis` - a list of dictionaries
+  - `template_axes` - a dictionary relating template names to properties that
+    should be used when expanding that particular template
+
+Internally, the tool creates a set of "subtests" for each template. This set is
+the Cartesian product of the `common_axis` and the given template's entry in
+the `template_axes` dictionary. It uses this set of subtests to expand the
+template, creating an output file. Refer to the next section for a concrete
+example of how the expansion is performed.
+
+In general, the tool will output a single file for each template. However, the
+`filename_flags` attribute has special semantics. It is used to separate
+subtests for the same template file. This is intended to accommodate [the
+web-platform-test's filename-based
+conventions](https://web-platform-tests.org/writing-tests/file-names.html).
+
+For instance, when `.https` is present in a test file's name, the WPT test
+harness will load that test using the HTTPS protocol. Subtests which include
+the value `https` in the `filename_flags` property will be expanded using the
+appropriate template but written to a distinct file whose name includes
+`.https`.
+
+The generation tool requires that the configuration file references every
+template in the `templates` directory. Because templates and configuration
+files may be contributed by different people, this requirement ensures that
+configuration authors are aware of all available templates. Some templates may
+not be relevant for some features; in those cases, the configuration file can
+include an empty array for the template's entry in the `template_axes`
+dictionary (as in `template3.html` in the example which follows).
+
+## Expansion example
+
+In the following example configuration file, `a`, `b`, `s`, `w`, `x`, `y`, and
+`z` all represent associative arrays.
+
+```yaml
+templates: path/to/templates
+output_directory: path/to/output
+cases:
+  - every_subtest: s
+    common_axis: [a, b]
+    template_axes:
+      template1.html: [w]
+      template2.html: [x, y, z]
+      template3.html: []
+```
+
+When run with such a configuration file, the tool would generate two files,
+expanded with data as described below (where `(a, b)` represents the union of
+`a` and `b`):
+
+    template1.html: [(a, w), (b, w)]
+    template2.html: [(a, x), (b, x), (a, y), (b, y), (a, z), (b, z)]
+    template3.html: (zero tests; not expanded)
+
+## Design Considerations
+
+**Efficiency of generated output** The tool is capable of generating a large
+number of tests given a small amount of input. Naively structured, this could
+result in test suites which take large amount of time and computational
+resources to complete. The tool has been designed to help authors structure the
+generated output to reduce these resource requirements.
+
+**Literalness of generated output** Because the generated output is how most
+people will interact with the tests, it is important that it be approachable.
+This tool avoids outputting abstractions which would frustrate attempts to read
+the source code or step through its execution environment.
+
+**Simplicity** The test generation logic itself was written to be approachable.
+This makes it easier to anticipate how the tool will behave with new input, and
+it lowers the bar for others to contribute improvements.
+
+Non-goals include conciseness of template files (verbosity makes the potential
+expansions more predictable) and conciseness of generated output (verbosity
+aids in the interpretation of results).
diff --git a/testing/web-platform/tests/fetch/metadata/tools/fetch-metadata.conf.yml b/testing/web-platform/tests/fetch/metadata/tools/fetch-metadata.conf.yml
new file mode 100644
index 0000000000..b277bcb7b5
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/fetch-metadata.conf.yml
@@ -0,0 +1,806 @@
+---
+templates: templates
+output_directory: ../generated
+cases:
+  - all_subtests:
+      expected: NULL
+      filename_flags: []
+    common_axis:
+      - headerName: sec-fetch-site
+        origins: [httpOrigin]
+        description: Not sent to non-trustworthy same-origin destination
+      - headerName: sec-fetch-site
+        origins: [httpSameSite]
+        description: Not sent to non-trustworthy same-site destination
+      - headerName: sec-fetch-site
+        origins: [httpCrossSite]
+        description: Not sent to non-trustworthy cross-site destination
+      - headerName: sec-fetch-mode
+        origins: [httpOrigin]
+        description: Not sent to non-trustworthy same-origin destination
+      - headerName: sec-fetch-mode
+        origins: [httpSameSite]
+        description: Not sent to non-trustworthy same-site destination
+      - headerName: sec-fetch-mode
+        origins: [httpCrossSite]
+        description: Not sent to non-trustworthy cross-site destination
+      - headerName: sec-fetch-dest
+        origins: [httpOrigin]
+        description: Not sent to non-trustworthy same-origin destination
+      - headerName: sec-fetch-dest
+        origins: [httpSameSite]
+        description: Not sent to non-trustworthy same-site destination
+      - headerName: sec-fetch-dest
+        origins: [httpCrossSite]
+        description: Not sent to non-trustworthy cross-site destination
+      - headerName: sec-fetch-user
+        origins: [httpOrigin]
+        description: Not sent to non-trustworthy same-origin destination
+      - headerName: sec-fetch-user
+        origins: [httpSameSite]
+        description: Not sent to non-trustworthy same-site destination
+      - headerName: sec-fetch-user
+        origins: [httpCrossSite]
+        description: Not sent to non-trustworthy cross-site destination
+    template_axes:
+      # Unused
+      appcache-manifest.sub.https.html: []
+      # The `audioWorklet` interface is only available in secure contexts
+      # https://webaudio.github.io/web-audio-api/#BaseAudioContext
+      audioworklet.https.sub.html: []
+      # Service workers are only available in secure context
+      fetch-via-serviceworker.https.sub.html: []
+      # Service workers are only available in secure context
+      serviceworker.https.sub.html: []
+
+      css-images.sub.html:
+        - filename_flags: [tentative]
+      css-font-face.sub.html:
+        - filename_flags: [tentative]
+      element-a.sub.html: [{}]
+      element-area.sub.html: [{}]
+      element-audio.sub.html: [{}]
+      element-embed.sub.html: [{}]
+      element-frame.sub.html: [{}]
+      element-iframe.sub.html: [{}]
+      element-img.sub.html:
+        - sourceAttr: src
+        - sourceAttr: srcset
+      element-img-environment-change.sub.html: [{}]
+      element-input-image.sub.html: [{}]
+      element-link-icon.sub.html: [{}]
+      element-link-prefetch.optional.sub.html: [{}]
+      element-meta-refresh.optional.sub.html: [{}]
+      element-picture.sub.html: [{}]
+      element-script.sub.html:
+        - {}
+        - elementAttrs: { type: module }
+      element-video.sub.html: [{}]
+      element-video-poster.sub.html: [{}]
+      fetch.sub.html: [{}]
+      form-submission.sub.html:
+        - method: GET
+        - method: POST
+      header-link.sub.html:
+        - rel: icon
+        - rel: stylesheet
+      header-refresh.optional.sub.html: [{}]
+      window-location.sub.html: [{}]
+      script-module-import-dynamic.sub.html: [{}]
+      script-module-import-static.sub.html: [{}]
+      svg-image.sub.html: [{}]
+      window-history.sub.html: [{}]
+      worker-dedicated-importscripts.sub.html: [{}]
+      worker-dedicated-constructor.sub.html: [{}]
+
+  # Sec-Fetch-Site - direct requests
+  - all_subtests:
+      headerName: sec-fetch-site
+      filename_flags: [https]
+    common_axis:
+      - description: Same origin
+        origins: [httpsOrigin]
+        expected: same-origin
+      - description: Cross-site
+        origins: [httpsCrossSite]
+        expected: cross-site
+      - description: Same site
+        origins: [httpsSameSite]
+        expected: same-site
+    template_axes:
+      # Unused
+      # - the request mode of all "classic" worker scripts is set to
+      #   "same-origin"
+      #   https://html.spec.whatwg.org/#fetch-a-classic-worker-script
+      # - the request mode of all "top-level "module" worker scripts is set to
+      #   "same-origin":
+      #   https://html.spec.whatwg.org/#fetch-a-single-module-script
+      worker-dedicated-constructor.sub.html: []
+
+      appcache-manifest.sub.https.html: [{}]
+      audioworklet.https.sub.html: [{}]
+      css-images.sub.html:
+        - filename_flags: [tentative]
+      css-font-face.sub.html:
+        - filename_flags: [tentative]
+      element-a.sub.html: [{}]
+      element-area.sub.html: [{}]
+      element-audio.sub.html: [{}]
+      element-embed.sub.html: [{}]
+      element-frame.sub.html: [{}]
+      element-iframe.sub.html: [{}]
+      element-img.sub.html:
+        - sourceAttr: src
+        - sourceAttr: srcset
+      element-img-environment-change.sub.html: [{}]
+      element-input-image.sub.html: [{}]
+      element-link-icon.sub.html: [{}]
+      element-link-prefetch.optional.sub.html: [{}]
+      element-meta-refresh.optional.sub.html: [{}]
+      element-picture.sub.html: [{}]
+      element-script.sub.html:
+        - {}
+        - elementAttrs: { type: module }
+      element-video.sub.html: [{}]
+      element-video-poster.sub.html: [{}]
+      fetch.sub.html: [{ init: { mode: no-cors } }]
+      fetch-via-serviceworker.https.sub.html: [{ init: { mode: no-cors } }]
+      form-submission.sub.html:
+        - method: GET
+        - method: POST
+      header-link.sub.html:
+        - rel: icon
+        - rel: stylesheet
+      header-refresh.optional.sub.html: [{}]
+      window-location.sub.html: [{}]
+      script-module-import-dynamic.sub.html: [{}]
+      script-module-import-static.sub.html: [{}]
+      serviceworker.https.sub.html: [{}]
+      svg-image.sub.html: [{}]
+      window-history.sub.html: [{}]
+      worker-dedicated-importscripts.sub.html: [{}]
+
+  # Sec-Fetch-Site - redirection from HTTP
+  - all_subtests:
+      headerName: sec-fetch-site
+      filename_flags: []
+    common_axis:
+      - description: HTTPS downgrade (header not sent)
+        origins: [httpsOrigin, httpOrigin]
+        expected: NULL
+      - description: HTTPS upgrade
+        origins: [httpOrigin, httpsOrigin]
+        expected: cross-site
+      - description: HTTPS downgrade-upgrade
+        origins: [httpsOrigin, httpOrigin, httpsOrigin]
+        expected: cross-site
+    template_axes:
+      # Unused
+      # The `audioWorklet` interface is only available in secure contexts
+      # https://webaudio.github.io/web-audio-api/#BaseAudioContext
+      audioworklet.https.sub.html: []
+      # Service workers are only available in secure context
+      fetch-via-serviceworker.https.sub.html: []
+      # Service workers' redirect mode is "error"
+      serviceworker.https.sub.html: []
+      # Interstitial locations in an HTTP redirect chain are not added to the
+      # session history, so these requests cannot be initiated using the
+      # History API.
+      window-history.sub.html: []
+      # Unused
+      # - the request mode of all "classic" worker scripts is set to
+      #   "same-origin"
+      #   https://html.spec.whatwg.org/#fetch-a-classic-worker-script
+      # - the request mode of all "top-level "module" worker scripts is set to
+      #   "same-origin":
+      #   https://html.spec.whatwg.org/#fetch-a-single-module-script
+      worker-dedicated-constructor.sub.html: []
+
+      appcache-manifest.sub.https.html: [{}]
+      css-images.sub.html:
+        - filename_flags: [tentative]
+      css-font-face.sub.html:
+        - filename_flags: [tentative]
+      element-a.sub.html: [{}]
+      element-area.sub.html: [{}]
+      element-audio.sub.html: [{}]
+      element-embed.sub.html: [{}]
+      element-frame.sub.html: [{}]
+      element-iframe.sub.html: [{}]
+      element-img.sub.html:
+        - sourceAttr: src
+        - sourceAttr: srcset
+      element-img-environment-change.sub.html: [{}]
+      element-input-image.sub.html: [{}]
+      element-link-icon.sub.html: [{}]
+      element-link-prefetch.optional.sub.html: [{}]
+      element-meta-refresh.optional.sub.html: [{}]
+      element-picture.sub.html: [{}]
+      element-script.sub.html:
+        - {}
+        - elementAttrs: { type: module }
+      element-video.sub.html: [{}]
+      element-video-poster.sub.html: [{}]
+      fetch.sub.html: [{}]
+      form-submission.sub.html:
+        - method: GET
+        - method: POST
+      header-link.sub.html:
+        - rel: icon
+        - rel: stylesheet
+      header-refresh.optional.sub.html: [{}]
+      window-location.sub.html: [{}]
+      script-module-import-dynamic.sub.html: [{}]
+      script-module-import-static.sub.html: [{}]
+      svg-image.sub.html: [{}]
+      worker-dedicated-importscripts.sub.html: [{}]
+
+  # Sec-Fetch-Site - redirection from HTTPS
+  - all_subtests:
+      headerName: sec-fetch-site
+      filename_flags: [https]
+    common_axis:
+      - description: Same-Origin -> Cross-Site -> Same-Origin redirect
+        origins: [httpsOrigin, httpsCrossSite, httpsOrigin]
+        expected: cross-site
+      - description: Same-Origin -> Same-Site -> Same-Origin redirect
+        origins: [httpsOrigin, httpsSameSite, httpsOrigin]
+        expected: same-site
+      - description: Cross-Site -> Same Origin
+        origins: [httpsCrossSite, httpsOrigin]
+        expected: cross-site
+      - description: Cross-Site -> Same-Site
+        origins: [httpsCrossSite, httpsSameSite]
+        expected: cross-site
+      - description: Cross-Site -> Cross-Site
+        origins: [httpsCrossSite, httpsCrossSite]
+        expected: cross-site
+      - description: Same-Origin -> Same Origin
+        origins: [httpsOrigin, httpsOrigin]
+        expected: same-origin
+      - description: Same-Origin -> Same-Site
+        origins: [httpsOrigin, httpsSameSite]
+        expected: same-site
+      - description: Same-Origin -> Cross-Site
+        origins: [httpsOrigin, httpsCrossSite]
+        expected: cross-site
+      - description: Same-Site -> Same Origin
+        origins: [httpsSameSite, httpsOrigin]
+        expected: same-site
+      - description: Same-Site -> Same-Site
+        origins: [httpsSameSite, httpsSameSite]
+        expected: same-site
+      - description: Same-Site -> Cross-Site
+        origins: [httpsSameSite, httpsCrossSite]
+        expected: cross-site
+    template_axes:
+      # Service Workers' redirect mode is "error"
+      serviceworker.https.sub.html: []
+      # Interstitial locations in an HTTP redirect chain are not added to the
+      # session history, so these requests cannot be initiated using the
+      # History API.
+      window-history.sub.html: []
+      # Unused
+      # - the request mode of all "classic" worker scripts is set to
+      #   "same-origin"
+      #   https://html.spec.whatwg.org/#fetch-a-classic-worker-script
+      # - the request mode of all "top-level "module" worker scripts is set to
+      #   "same-origin":
+      #   https://html.spec.whatwg.org/#fetch-a-single-module-script
+      worker-dedicated-constructor.sub.html: []
+
+      appcache-manifest.sub.https.html: [{}]
+      audioworklet.https.sub.html: [{}]
+      css-images.sub.html:
+        - filename_flags: [tentative]
+      css-font-face.sub.html:
+        - filename_flags: [tentative]
+      element-a.sub.html: [{}]
+      element-area.sub.html: [{}]
+      element-audio.sub.html: [{}]
+      element-embed.sub.html: [{}]
+      element-frame.sub.html: [{}]
+      element-iframe.sub.html: [{}]
+      element-img.sub.html:
+        - sourceAttr: src
+        - sourceAttr: srcset
+      element-img-environment-change.sub.html: [{}]
+      element-input-image.sub.html: [{}]
+      element-link-icon.sub.html: [{}]
+      element-link-prefetch.optional.sub.html: [{}]
+      element-meta-refresh.optional.sub.html: [{}]
+      element-picture.sub.html: [{}]
+      element-script.sub.html:
+        - {}
+        - elementAttrs: { type: module }
+      element-video.sub.html: [{}]
+      element-video-poster.sub.html: [{}]
+      fetch.sub.html: [{ init: { mode: no-cors } }]
+      fetch-via-serviceworker.https.sub.html: [{ init: { mode: no-cors } }]
+      form-submission.sub.html:
+        - method: GET
+        - method: POST
+      header-link.sub.html:
+        - rel: icon
+        - rel: stylesheet
+      header-refresh.optional.sub.html: [{}]
+      window-location.sub.html: [{}]
+      script-module-import-dynamic.sub.html: [{}]
+      script-module-import-static.sub.html: [{}]
+      svg-image.sub.html: [{}]
+      worker-dedicated-importscripts.sub.html: [{}]
+
+  # Sec-Fetch-Site - redirection with mixed content
+  # These tests verify the effect that redirection has on the request's "site".
+  # The initial request must be made to a resource that is "same-site" with its
+  # origin. This avoids false positives because if the request were made to a
+  # cross-site resource, the value of "cross-site" would be assigned regardless
+  # of the subseqent redirection.
+  #
+  # Because these conditions necessarily warrant mixed content, only templates
+  # which can be configured to allow mixed content [1] can be used.
+  #
+  # [1] https://w3c.github.io/webappsec-mixed-content/#should-block-fetch
+
+  - common_axis:
+      - description: HTTPS downgrade-upgrade
+        headerName: sec-fetch-site
+        origins: [httpsOrigin, httpOrigin, httpsOrigin]
+        expected: cross-site
+        filename_flags: [https]
+    template_axes:
+      # Mixed Content considers only a small subset of requests as
+      # "optionally-blockable." These are the only requests that can be tested
+      # for the "downgrade-upgrade" scenario, so all other templates must be
+      # explicitly ignored.
+      audioworklet.https.sub.html: []
+      css-font-face.sub.html: []
+      element-embed.sub.html: []
+      element-frame.sub.html: []
+      element-iframe.sub.html: []
+      element-img-environment-change.sub.html: []
+      element-link-icon.sub.html: []
+      element-link-prefetch.optional.sub.html: []
+      element-picture.sub.html: []
+      element-script.sub.html: []
+      fetch.sub.html: []
+      fetch-via-serviceworker.https.sub.html: []
+      header-link.sub.html: []
+      script-module-import-static.sub.html: []
+      script-module-import-dynamic.sub.html: []
+      # Service Workers' redirect mode is "error"
+      serviceworker.https.sub.html: []
+      # Interstitial locations in an HTTP redirect chain are not added to the
+      # session history, so these requests cannot be initiated using the
+      # History API.
+      window-history.sub.html: []
+      worker-dedicated-constructor.sub.html: []
+      worker-dedicated-importscripts.sub.html: []
+      # Avoid duplicate subtest for 'sec-fetch-site - HTTPS downgrade-upgrade'
+      appcache-manifest.sub.https.html: []
+      css-images.sub.html:
+        - filename_flags: [tentative]
+      element-a.sub.html: [{}]
+      element-area.sub.html: [{}]
+      element-audio.sub.html: [{}]
+      element-img.sub.html:
+        # srcset omitted because it is not "optionally-blockable"
+        # https://w3c.github.io/webappsec-mixed-content/#category-optionally-blockable
+        - sourceAttr: src
+      element-input-image.sub.html: [{}]
+      element-meta-refresh.optional.sub.html: [{}]
+      element-video.sub.html: [{}]
+      element-video-poster.sub.html: [{}]
+      form-submission.sub.html:
+        - method: GET
+        - method: POST
+      header-refresh.optional.sub.html: [{}]
+      svg-image.sub.html: [{}]
+      window-location.sub.html: [{}]
+
+  # Sec-Fetch-Mode
+  # These tests are served over HTTPS so the induced requests will be both
+  # same-origin with the document [1] and a potentially-trustworthy URL [2].
+  #
+  # [1] https://html.spec.whatwg.org/multipage/origin.html#same-origin
+  # [2] https://w3c.github.io/webappsec-secure-contexts/#potentially-trustworthy-url
+  - common_axis:
+      - headerName: sec-fetch-mode
+        filename_flags: [https]
+        origins: []
+    template_axes:
+      appcache-manifest.sub.https.html:
+        - expected: no-cors
+      audioworklet.https.sub.html:
+        # https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-single-module-script
+        - expected: cors
+      css-images.sub.html:
+        - expected: no-cors
+          filename_flags: [tentative]
+      css-font-face.sub.html:
+        - expected: cors
+          filename_flags: [tentative]
+      element-a.sub.html:
+        - expected: navigate
+        # https://html.spec.whatwg.org/multipage/links.html#downloading-hyperlinks
+        - elementAttrs: {download: ''}
+          expected: no-cors
+      element-area.sub.html:
+        - expected: navigate
+        # https://html.spec.whatwg.org/multipage/links.html#downloading-hyperlinks
+        - elementAttrs: {download: ''}
+          expected: no-cors
+      element-audio.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-embed.sub.html:
+        - expected: no-cors
+      element-frame.sub.html:
+        - expected: navigate
+      element-iframe.sub.html:
+        - expected: navigate
+      element-img.sub.html:
+        - sourceAttr: src
+          expected: no-cors
+        - sourceAttr: src
+          expected: cors
+          elementAttrs: { crossorigin: '' }
+        - sourceAttr: src
+          expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - sourceAttr: src
+          expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+        - sourceAttr: srcset
+          expected: no-cors
+        - sourceAttr: srcset
+          expected: cors
+          elementAttrs: { crossorigin: '' }
+        - sourceAttr: srcset
+          expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - sourceAttr: srcset
+          expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-img-environment-change.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-input-image.sub.html:
+        - expected: no-cors
+      element-link-icon.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-link-prefetch.optional.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-meta-refresh.optional.sub.html:
+        - expected: navigate
+      element-picture.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-script.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { type: module }
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-video.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      element-video-poster.sub.html:
+        - expected: no-cors
+      fetch.sub.html:
+        - expected: cors
+        - expected: cors
+          init: { mode: cors }
+        - expected: no-cors
+          init: { mode: no-cors }
+        - expected: same-origin
+          init: { mode: same-origin }
+      fetch-via-serviceworker.https.sub.html:
+        - expected: cors
+        - expected: cors
+          init: { mode: cors }
+        - expected: no-cors
+          init: { mode: no-cors }
+        - expected: same-origin
+          init: { mode: same-origin }
+      form-submission.sub.html:
+        - method: GET
+          expected: navigate
+        - method: POST
+          expected: navigate
+      header-link.sub.html:
+        - rel: icon
+          expected: no-cors
+        - rel: stylesheet
+          expected: no-cors
+      header-refresh.optional.sub.html:
+        - expected: navigate
+      window-history.sub.html:
+        - expected: navigate
+      window-location.sub.html:
+        - expected: navigate
+      script-module-import-dynamic.sub.html:
+        - expected: cors
+      script-module-import-static.sub.html:
+        - expected: cors
+      # https://svgwg.org/svg2-draft/linking.html#processingURL-fetch
+      svg-image.sub.html:
+        - expected: no-cors
+        - expected: cors
+          elementAttrs: { crossorigin: '' }
+        - expected: cors
+          elementAttrs: { crossorigin: anonymous }
+        - expected: cors
+          elementAttrs: { crossorigin: use-credentials }
+      serviceworker.https.sub.html:
+        - expected: same-origin
+          options: { type: 'classic' }
+        # https://github.com/whatwg/html/pull/5875
+        - expected: same-origin
+      worker-dedicated-constructor.sub.html:
+        - expected: same-origin
+        - options: { type: module }
+          expected: same-origin
+      worker-dedicated-importscripts.sub.html:
+        - expected: no-cors
+
+  # Sec-Fetch-Dest
+  - common_axis:
+      - headerName: sec-fetch-dest
+        filename_flags: [https]
+        origins: []
+    template_axes:
+      appcache-manifest.sub.https.html:
+        - expected: empty
+      audioworklet.https.sub.html:
+        # https://github.com/WebAudio/web-audio-api/issues/2203
+        - expected: audioworklet
+      css-images.sub.html:
+        - expected: image
+          filename_flags: [tentative]
+      css-font-face.sub.html:
+        - expected: font
+          filename_flags: [tentative]
+      element-a.sub.html:
+        - expected: document
+        # https://html.spec.whatwg.org/multipage/links.html#downloading-hyperlinks
+        - elementAttrs: {download: ''}
+          expected: empty
+      element-area.sub.html:
+        - expected: document
+        # https://html.spec.whatwg.org/multipage/links.html#downloading-hyperlinks
+        - elementAttrs: {download: ''}
+          expected: empty
+      element-audio.sub.html:
+        - expected: audio
+      element-embed.sub.html:
+        - expected: embed
+      element-frame.sub.html:
+        # https://github.com/whatwg/html/pull/4976
+        - expected: frame
+      element-iframe.sub.html:
+        # https://github.com/whatwg/html/pull/4976
+        - expected: iframe
+      element-img.sub.html:
+        - sourceAttr: src
+          expected: image
+        - sourceAttr: srcset
+          expected: image
+      element-img-environment-change.sub.html:
+        - expected: image
+      element-input-image.sub.html:
+        - expected: image
+      element-link-icon.sub.html:
+        - expected: empty
+      element-link-prefetch.optional.sub.html:
+        - expected: empty
+        - elementAttrs: { as: audio }
+          expected: audio
+        - elementAttrs: { as: document }
+          expected: document
+        - elementAttrs: { as: embed }
+          expected: embed
+        - elementAttrs: { as: fetch }
+          expected: fetch
+        - elementAttrs: { as: font }
+          expected: font
+        - elementAttrs: { as: image }
+          expected: image
+        - elementAttrs: { as: object }
+          expected: object
+        - elementAttrs: { as: script }
+          expected: script
+        - elementAttrs: { as: style }
+          expected: style
+        - elementAttrs: { as: track }
+          expected: track
+        - elementAttrs: { as: video }
+          expected: video
+        - elementAttrs: { as: worker }
+          expected: worker
+      element-meta-refresh.optional.sub.html:
+        - expected: document
+      element-picture.sub.html:
+        - expected: image
+      element-script.sub.html:
+        - expected: script
+      element-video.sub.html:
+        - expected: video
+      element-video-poster.sub.html:
+        - expected: image
+      fetch.sub.html:
+        - expected: empty
+      fetch-via-serviceworker.https.sub.html:
+        - expected: empty
+      form-submission.sub.html:
+        - method: GET
+          expected: document
+        - method: POST
+          expected: document
+      header-link.sub.html:
+        - rel: icon
+          expected: empty
+        - rel: stylesheet
+          filename_flags: [tentative]
+          expected: style
+      header-refresh.optional.sub.html:
+        - expected: document
+      window-history.sub.html:
+        - expected: document
+      window-location.sub.html:
+        - expected: document
+      script-module-import-dynamic.sub.html:
+        - expected: script
+      script-module-import-static.sub.html:
+        - expected: script
+      serviceworker.https.sub.html:
+        - expected: serviceworker
+      # Implemented as "image" in Chromium and Firefox, but specified as
+      # "empty"
+      # https://github.com/w3c/svgwg/issues/782
+      svg-image.sub.html:
+        - expected: empty
+      worker-dedicated-constructor.sub.html:
+        - expected: worker
+        - options: { type: module }
+          expected: worker
+      worker-dedicated-importscripts.sub.html:
+        - expected: script
+
+  # Sec-Fetch-User
+  - common_axis:
+      - headerName: sec-fetch-user
+        filename_flags: [https]
+        origins: []
+    template_axes:
+      appcache-manifest.sub.https.html:
+        - expected: NULL
+      audioworklet.https.sub.html:
+        - expected: NULL
+      css-images.sub.html:
+        - expected: NULL
+          filename_flags: [tentative]
+      css-font-face.sub.html:
+        - expected: NULL
+          filename_flags: [tentative]
+      element-a.sub.html:
+        - expected: NULL
+        - userActivated: TRUE
+          expected: ?1
+      element-area.sub.html:
+        - expected: NULL
+        - userActivated: TRUE
+          expected: ?1
+      element-audio.sub.html:
+        - expected: NULL
+      element-embed.sub.html:
+        - expected: NULL
+      element-frame.sub.html:
+        - expected: NULL
+        - userActivated: TRUE
+          expected: ?1
+      element-iframe.sub.html:
+        - expected: NULL
+        - userActivated: TRUE
+          expected: ?1
+      element-img.sub.html:
+        - sourceAttr: src
+          expected: NULL
+        - sourceAttr: srcset
+          expected: NULL
+      element-img-environment-change.sub.html:
+        - expected: NULL
+      element-input-image.sub.html:
+        - expected: NULL
+      element-link-icon.sub.html:
+        - expected: NULL
+      element-link-prefetch.optional.sub.html:
+        - expected: NULL
+      element-meta-refresh.optional.sub.html:
+        - expected: NULL
+      element-picture.sub.html:
+        - expected: NULL
+      element-script.sub.html:
+        - expected: NULL
+      element-video.sub.html:
+        - expected: NULL
+      element-video-poster.sub.html:
+        - expected: NULL
+      fetch.sub.html:
+        - expected: NULL
+      fetch-via-serviceworker.https.sub.html:
+        - expected: NULL
+      form-submission.sub.html:
+        - method: GET
+          expected: NULL
+        - method: GET
+          userActivated: TRUE
+          expected: ?1
+        - method: POST
+          expected: NULL
+        - method: POST
+          userActivated: TRUE
+          expected: ?1
+      header-link.sub.html:
+        - rel: icon
+          expected: NULL
+        - rel: stylesheet
+          expected: NULL
+      header-refresh.optional.sub.html:
+        - expected: NULL
+      window-history.sub.html:
+        - expected: NULL
+      window-location.sub.html:
+        - expected: NULL
+        - userActivated: TRUE
+          expected: ?1
+      script-module-import-dynamic.sub.html:
+        - expected: NULL
+      script-module-import-static.sub.html:
+        - expected: NULL
+      serviceworker.https.sub.html:
+        - expected: NULL
+      svg-image.sub.html:
+        - expected: NULL
+      worker-dedicated-constructor.sub.html:
+        - expected: NULL
+        - options: { type: module }
+          expected: NULL
+      worker-dedicated-importscripts.sub.html:
+        - expected: NULL
diff --git a/testing/web-platform/tests/fetch/metadata/tools/generate.py b/testing/web-platform/tests/fetch/metadata/tools/generate.py
new file mode 100755
index 0000000000..fa850c8c8a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/generate.py
@@ -0,0 +1,195 @@
+#!/usr/bin/env python3
+
+import itertools
+import os
+
+import jinja2
+import yaml
+
+HERE = os.path.abspath(os.path.dirname(__file__))
+PROJECT_ROOT = os.path.join(HERE, '..', '..', '..')
+
+def find_templates(starting_directory):
+    for directory, subdirectories, file_names in os.walk(starting_directory):
+        for file_name in file_names:
+            if file_name.startswith('.'):
+                continue
+            yield file_name, os.path.join(directory, file_name)
+
+def test_name(directory, template_name, subtest_flags):
+    '''
+    Create a test name based on a template and the WPT file name flags [1]
+    required for a given subtest. This name is used to determine how subtests
+    may be grouped together. In order to promote grouping, the combination uses
+    a few aspects of how file name flags are interpreted:
+
+    - repeated flags have no effect, so duplicates are removed
+    - flag sequence does not matter, so flags are consistently sorted
+
+    directory | template_name    | subtest_flags   | result
+    ----------|------------------|-----------------|-------
+    cors      | image.html       | []              | cors/image.html
+    cors      | image.https.html | []              | cors/image.https.html
+    cors      | image.html       | [https]         | cors/image.https.html
+    cors      | image.https.html | [https]         | cors/image.https.html
+    cors      | image.https.html | [https]         | cors/image.https.html
+    cors      | image.sub.html   | [https]         | cors/image.https.sub.html
+    cors      | image.https.html | [sub]           | cors/image.https.sub.html
+
+    [1] docs/writing-tests/file-names.md
+    '''
+    template_name_parts = template_name.split('.')
+    flags = set(subtest_flags) | set(template_name_parts[1:-1])
+    test_name_parts = (
+        [template_name_parts[0]] +
+        sorted(flags) +
+        [template_name_parts[-1]]
+    )
+    return os.path.join(directory, '.'.join(test_name_parts))
+
+def merge(a, b):
+    if type(a) != type(b):
+        raise Exception('Cannot merge disparate types')
+    if type(a) == list:
+        return a + b
+    if type(a) == dict:
+        merged = {}
+
+        for key in a:
+            if key in b:
+                merged[key] = merge(a[key], b[key])
+            else:
+                merged[key] = a[key]
+
+        for key in b:
+            if not key in a:
+                merged[key] = b[key]
+
+        return merged
+
+    raise Exception('Cannot merge {} type'.format(type(a).__name__))
+
+def product(a, b):
+    '''
+    Given two lists of objects, compute their Cartesian product by merging the
+    elements together. For example,
+
+       product(
+           [{'a': 1}, {'b': 2}],
+           [{'c': 3}, {'d': 4}, {'e': 5}]
+       )
+
+    returns the following list:
+
+        [
+            {'a': 1, 'c': 3},
+            {'a': 1, 'd': 4},
+            {'a': 1, 'e': 5},
+            {'b': 2, 'c': 3},
+            {'b': 2, 'd': 4},
+            {'b': 2, 'e': 5}
+        ]
+    '''
+    result = []
+
+    for a_object in a:
+        for b_object in b:
+            result.append(merge(a_object, b_object))
+
+    return result
+
+def make_provenance(project_root, cases, template):
+    return '\n'.join([
+        'This test was procedurally generated. Please do not modify it directly.',
+        'Sources:',
+        '- {}'.format(os.path.relpath(cases, project_root)),
+        '- {}'.format(os.path.relpath(template, project_root))
+    ])
+
+def collection_filter(obj, title):
+    if not obj:
+        return 'no {}'.format(title)
+
+    members = []
+    for name, value in obj.items():
+        if value == '':
+            members.append(name)
+        else:
+            members.append('{}={}'.format(name, value))
+
+    return '{}: {}'.format(title, ', '.join(members))
+
+def pad_filter(value, side, padding):
+    if not value:
+        return ''
+    if side == 'start':
+        return padding + value
+
+    return value + padding
+
+def main(config_file):
+    with open(config_file, 'r') as handle:
+        config = yaml.safe_load(handle.read())
+
+    templates_directory = os.path.normpath(
+        os.path.join(os.path.dirname(config_file), config['templates'])
+    )
+
+    environment = jinja2.Environment(
+        variable_start_string='[%',
+        variable_end_string='%]'
+    )
+    environment.filters['collection'] = collection_filter
+    environment.filters['pad'] = pad_filter
+    templates = {}
+    subtests = {}
+
+    for template_name, path in find_templates(templates_directory):
+        subtests[template_name] = []
+        with open(path, 'r') as handle:
+            templates[template_name] = environment.from_string(handle.read())
+
+    for case in config['cases']:
+        unused_templates = set(templates) - set(case['template_axes'])
+
+        # This warning is intended to help authors avoid mistakenly omitting
+        # templates. It can be silenced by extending the`template_axes`
+        # dictionary with an empty list for templates which are intentionally
+        # unused.
+        if unused_templates:
+            print(
+                'Warning: case does not reference the following templates:'
+            )
+            print('\n'.join('- {}'.format(name) for name in unused_templates))
+
+        common_axis = product(
+            case['common_axis'], [case.get('all_subtests', {})]
+        )
+
+        for template_name, template_axis in case['template_axes'].items():
+            subtests[template_name].extend(product(common_axis, template_axis))
+
+    for template_name, template in templates.items():
+        provenance = make_provenance(
+            PROJECT_ROOT,
+            config_file,
+            os.path.join(templates_directory, template_name)
+        )
+        get_filename = lambda subtest: test_name(
+            config['output_directory'],
+            template_name,
+            subtest['filename_flags']
+        )
+        subtests_by_filename = itertools.groupby(
+            sorted(subtests[template_name], key=get_filename),
+            key=get_filename
+        )
+        for filename, some_subtests in subtests_by_filename:
+            with open(filename, 'w') as handle:
+                handle.write(templates[template_name].render(
+                    subtests=list(some_subtests),
+                    provenance=provenance
+                ) + '\n')
+
+if __name__ == '__main__':
+    main('fetch-metadata.conf.yml')
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/appcache-manifest.sub.https.html b/testing/web-platform/tests/fetch/metadata/tools/templates/appcache-manifest.sub.https.html
new file mode 100644
index 0000000000..0dfc084f2e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/appcache-manifest.sub.https.html
@@ -0,0 +1,63 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for Appcache manifest</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url) {
+    const iframe = document.createElement('iframe');
+    iframe.src =
+      '/fetch/metadata/resources/appcache-iframe.sub.html?manifest=' + encodeURIComponent(url);
+
+    return new Promise((resolve) => {
+        addEventListener('message', function onMessage(event) {
+          if (event.source !== iframe.contentWindow) {
+            return;
+          }
+          removeEventListener('message', onMessage);
+          resolve(event.data);
+        });
+
+        document.body.appendChild(iframe);
+      })
+      .then((message) => {
+        if (message !== 'okay') {
+          throw message;
+        }
+      })
+      .then(() => iframe.remove());
+  }
+
+  {%- for subtest in subtests %}
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    assert_implements_optional(
+      !!window.applicationCache, 'Application Cache supported.'
+    );
+
+    induceRequest(makeRequestURL(key, [% subtest.origins %]))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      })
+      .then(() => t.done(), t.step_func((error) => { throw error; }));
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/audioworklet.https.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/audioworklet.https.sub.html
new file mode 100644
index 0000000000..7be309c506
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/audioworklet.https.sub.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for AudioWorklet module</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    return test_driver.bless(
+      'Enable WebAudio playback',
+      () => {
+        const audioContext = new AudioContext();
+
+        test.add_cleanup(() => audioContext.close());
+
+        return audioContext.audioWorklet.addModule(url);
+      }
+    );
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], {mime: 'text/javascript'}),
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/css-font-face.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/css-font-face.sub.html
new file mode 100644
index 0000000000..94b33f4e6b
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/css-font-face.sub.html
@@ -0,0 +1,60 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for CSS font-face</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  let count = 0;
+
+  function induceRequest(t, url) {
+    const id = `el-${count += 1}`;
+    const style = document.createElement('style');
+    style.appendChild(document.createTextNode(`
+      @font-face {
+        font-family: wpt-font-family${id};
+        src: url(${url});
+      }
+      #el-${id} {
+        font-family: wpt-font-family${id};
+      }
+    `));
+    const div = document.createElement('div');
+    div.setAttribute('id', 'el-' + id);
+    div.appendChild(style);
+    div.appendChild(document.createTextNode('x'));
+    document.body.appendChild(div);
+
+    t.add_cleanup(() => div.remove());
+
+    return document.fonts.ready;
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [% subtest.origins %]))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/css-images.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/css-images.sub.html
new file mode 100644
index 0000000000..e394f9f5b0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/css-images.sub.html
@@ -0,0 +1,137 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for CSS image-accepting properties</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The subtests in this file use an iframe to induce requests for CSS
+   * resources because an iframe's `onload` event is the most direct and
+   * generic mechanism to detect loading of CSS resources. As an optimization,
+   * the subtests share the same iframe and document.
+   */
+  const declarations = [];
+  const iframe = document.createElement('iframe');
+  const whenIframeReady = new Promise((resolve, reject) => {
+    iframe.onload = resolve;
+    iframe.onerror = reject;
+  });
+
+  {%- for subtest in subtests %}
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %]);
+
+    declarations.push(`background-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_equals(headers['[%subtest.headerName%]'], '[%subtest.expected%]');
+        {%- endif %}
+        })
+        .then(t.step_func_done(), (error) => t.unreached_func());
+  }, 'background-image [%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %]);
+
+    declarations.push(`border-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'border-image [%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %]);
+
+    declarations.push(`content: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'content [%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %]);
+
+    declarations.push(`cursor: url("${url}"), auto;`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'cursor [%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  async_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %]);
+
+    declarations.push(`list-style-image: url("${url}");`);
+
+    whenIframeReady
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        })
+      .then(t.step_func_done(), t.unreached_func());
+  }, 'list-style-image [%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+
+  iframe.srcdoc = declarations.map((declaration, index) => `
+    <style>.el${index} { ${declaration} }</style><div class="el${index}"></div>`
+    ).join('');
+  document.body.appendChild(iframe);
+
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-a.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-a.sub.html
new file mode 100644
index 0000000000..2bd8e8a40e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-a.sub.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for HTML "a" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const anchor = win.document.createElement('a');
+    anchor.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      anchor.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(anchor);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => anchor.click());
+    } else {
+      anchor.click();
+    }
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [% subtest.origins %], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: [%subtest.userActivated | default(false) | tojson%],
+        attributes: [%subtest.elementAttrs | default({}) | tojson%]
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%] - [%subtest.elementAttrs | collection("attributes")%][% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-area.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-area.sub.html
new file mode 100644
index 0000000000..0cef5b2294
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-area.sub.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for HTML "area" element navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, {test, userActivated, attributes}) {
+    const win = window.open();
+    const area = win.document.createElement('area');
+    area.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      area.setAttribute(name, value);
+    }
+
+    win.document.body.appendChild(area);
+
+    test.add_cleanup(() => win.close());
+
+    if (userActivated) {
+      test_driver.bless('enable user activation', () => area.click());
+    } else {
+      area.click();
+    }
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      makeRequestURL(key, [% subtest.origins %], {mime: 'text/html'}),
+      {
+        test: t,
+        userActivated: [%subtest.userActivated | default(false) | tojson%],
+        attributes: [%subtest.elementAttrs | default({}) | tojson%]
+      }
+    );
+
+    // `induceRequest` does not necessarily trigger a navigation, so the Python
+    // handler must be polled until it has received the initial request.
+    return retrieve(key, {poll: true})
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%] - [%subtest.elementAttrs | collection("attributes")%][% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-audio.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-audio.sub.html
new file mode 100644
index 0000000000..92bc22198e
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-audio.sub.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "audio" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const audio = document.createElement('audio');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      audio.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        audio.setAttribute('src', url);
+        audio.onload = audio.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-embed.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-embed.sub.html
new file mode 100644
index 0000000000..18ce09e5fd
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-embed.sub.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "embed" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    const embed = document.createElement('embed');
+    embed.setAttribute('src', url);
+    document.body.appendChild(embed);
+
+    t.add_cleanup(() => embed.remove());
+
+    return new Promise((resolve) => embed.addEventListener('load', resolve));
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [% subtest.origins %], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-frame.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-frame.sub.html
new file mode 100644
index 0000000000..ce90171779
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-frame.sub.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const frame = document.createElement('frame');
+
+    const setSrc = () => frame.setAttribute('src', url);
+
+    document.body.appendChild(frame);
+    test.add_cleanup(() => frame.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        frame.onload = frame.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], {mime: 'text/html'}),
+        t,
+        [%subtest.userActivated | default(false) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%][% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-iframe.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-iframe.sub.html
new file mode 100644
index 0000000000..43a632a15c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-iframe.sub.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "frame" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test, userActivated) {
+    const iframe = document.createElement('iframe');
+
+    const setSrc = () => iframe.setAttribute('src', url);
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+       if (userActivated) {
+         test_driver.bless('enable user activation', setSrc);
+       } else {
+         setSrc();
+       }
+
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], {mime: 'text/html'}),
+        t,
+        [%subtest.userActivated | default(false) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%][% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-img-environment-change.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-img-environment-change.sub.html
new file mode 100644
index 0000000000..5a65114f18
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-img-environment-change.sub.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on image request triggered by change to environment</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  // The response to the request under test must describe a valid image
+  // resource in order for the `load` event to be fired.
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const iframe = document.createElement('iframe');
+    iframe.style.width = '50px';
+    document.body.appendChild(iframe);
+    t.add_cleanup(() => iframe.remove());
+    iframe.contentDocument.open();
+    iframe.contentDocument.close();
+
+    const image = iframe.contentDocument.createElement('img');
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+    iframe.contentDocument.body.appendChild(image);
+
+    image.setAttribute('srcset', `${url} 100w, /media/1x1-green.png 1w`);
+    image.setAttribute('sizes', '(max-width: 100px) 1px, (min-width: 150px) 123px');
+
+    return new Promise((resolve) => {
+        image.onload = image.onerror = resolve;
+      })
+      .then(() => {
+
+        iframe.style.width = '200px';
+
+        return new Promise((resolve) => image.onload = resolve);
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [% subtest.origins %], params),
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-img.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-img.sub.html
new file mode 100644
index 0000000000..1dac5843ec
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-img.sub.html
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "img" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceAttr, attributes) {
+    const image = document.createElement('img');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        image.setAttribute(sourceAttr, url);
+        image.onload = image.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        '[%subtest.sourceAttr%]',
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.sourceAttr%] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-input-image.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-input-image.sub.html
new file mode 100644
index 0000000000..3c50008433
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-input-image.sub.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "input" element with type="button"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const input = document.createElement('input');
+    input.setAttribute('type', 'image');
+
+    document.body.appendChild(input);
+    test.add_cleanup(() => input.remove());
+
+    return new Promise((resolve) => {
+        input.onload = input.onerror = resolve;
+        input.setAttribute('src', url);
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(makeRequestURL(key, [% subtest.origins %]), t)
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-icon.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-icon.sub.html
new file mode 100644
index 0000000000..18ce12a689
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-icon.sub.html
@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for HTML "link" element with rel="icon"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'icon');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [% subtest.origins %], params),
+      [%subtest.elementAttrs | default({}) | tojson%]
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%] [%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-prefetch.optional.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-prefetch.optional.sub.html
new file mode 100644
index 0000000000..59d677d8d6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-link-prefetch.optional.sub.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for HTML "link" element with rel="prefetch"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  /**
+   * The `link` element supports a `load` event. That event would reliably
+   * indicate that the browser had received the request. Multiple major
+   * browsers do not implement the event, however, so in order to promote the
+   * visibility of this test, a less efficient polling-based detection
+   * mechanism is used.
+   *
+   * https://bugzilla.mozilla.org/show_bug.cgi?id=1638188
+   * https://bugs.chromium.org/p/chromium/issues/detail?id=1083034
+   */
+  function induceRequest(t, url, attributes) {
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'prefetch');
+    link.setAttribute('href', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      link.setAttribute(name, value);
+    }
+
+    document.head.appendChild(link);
+    t.add_cleanup(() => link.remove());
+  }
+
+  setup(() => {
+    assert_implements_optional(document.createElement('link').relList.supports('prefetch'));
+  });
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    induceRequest(
+      t,
+      makeRequestURL(key, [% subtest.origins %]),
+      [%subtest.elementAttrs | default({}) | tojson%]
+    );
+
+    return retrieve(key, {poll:true})
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%] [%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-meta-refresh.optional.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-meta-refresh.optional.sub.html
new file mode 100644
index 0000000000..5a8d8f8ecd
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-meta-refresh.optional.sub.html
@@ -0,0 +1,60 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "meta" element with http-equiv="refresh"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.document.open();
+    win.document.write(
+      `<meta http-equiv="Refresh" content="0; URL=${url}">`
+    );
+    win.document.close();
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-picture.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-picture.sub.html
new file mode 100644
index 0000000000..903aeed1f3
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-picture.sub.html
@@ -0,0 +1,101 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "picture" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, sourceEl, sourceAttr, attributes) {
+    const picture = document.createElement('picture');
+    const els = {
+      img: document.createElement('img'),
+      source: document.createElement('source')
+    };
+    picture.appendChild(els.source);
+    picture.appendChild(els.img);
+    document.body.appendChild(picture);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      els.img.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        els[sourceEl].setAttribute(sourceAttr, url);
+        els.img.onload = els.img.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        'img',
+        'src',
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - img[src] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        'img',
+        'srcset',
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - img[srcset] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        'source',
+        'srcset',
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - source[srcset] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
+
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-script.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-script.sub.html
new file mode 100644
index 0000000000..4a281ae519
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-script.sub.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "script" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const script = document.createElement('script');
+    script.setAttribute('src', url);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      script.setAttribute(name, value);
+    }
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [% subtest.origins %], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url,
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%-subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-video-poster.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-video-poster.sub.html
new file mode 100644
index 0000000000..9cdaf063ac
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-video-poster.sub.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element "poster"</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url) {
+    var video = document.createElement('video');
+    video.setAttribute('poster', url);
+    document.body.appendChild(video);
+
+    const poll = () => {
+      if (video.clientWidth === 123) {
+        return;
+      }
+
+      return new Promise((resolve) => t.step_timeout(resolve, 0))
+        .then(poll);
+    };
+    t.add_cleanup(() => video.remove());
+
+    return poll();
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(t, makeRequestURL(key, [% subtest.origins %], params))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/element-video.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/element-video.sub.html
new file mode 100644
index 0000000000..1b7b976d7c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/element-video.sub.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTML "video" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, attributes) {
+    const video = document.createElement('video');
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      video.setAttribute(name, value);
+    }
+
+    return new Promise((resolve) => {
+        video.setAttribute('src', url);
+        video.onload = video.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/fetch-via-serviceworker.https.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/fetch-via-serviceworker.https.sub.html
new file mode 100644
index 0000000000..eead710200
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/fetch-via-serviceworker.https.sub.html
@@ -0,0 +1,88 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request using the "fetch" API and passing through a Serive Worker</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const scripts = {
+    fallback: '/fetch/metadata/resources/fetch-via-serviceworker--fallback--sw.js',
+    respondWith: '/fetch/metadata/resources/fetch-via-serviceworker--respondWith--sw.js'
+  };
+
+  function induceRequest(t, url, init, script) {
+    const SCOPE = '/fetch/metadata/resources/fetch-via-serviceworker-frame.html';
+    const SCRIPT = scripts[script];
+
+    return service_worker_unregister_and_register(t, SCRIPT, SCOPE)
+      .then((registration) => {
+        t.add_cleanup(() => registration.unregister());
+
+        return wait_for_state(t, registration.installing, 'activated');
+      })
+      .then(() => with_iframe(SCOPE))
+      .then((frame) => {
+        t.add_cleanup(() => frame.remove());
+
+        return frame.contentWindow.fetch(url, init);
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [% subtest.origins %]),
+        [%subtest.init | default({}) | tojson%],
+        'respondWith'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.init | collection("init")%] - respondWith');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [% subtest.origins %]),
+        [%subtest.init | default({}) | tojson%],
+        'fallback'
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.init | collection("init")%] - fallback');
+
+  {%- endfor %}
+
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/fetch.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/fetch.sub.html
new file mode 100644
index 0000000000..a8dc5368f8
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/fetch.sub.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request using the "fetch" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, init) {
+    return fetch(url, init);
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %]),
+        [%subtest.init | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.init | collection("init")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/form-submission.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/form-submission.sub.html
new file mode 100644
index 0000000000..4c9c8c50f8
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/form-submission.sub.html
@@ -0,0 +1,87 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <title>HTTP headers on request for HTML form navigation</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(method, url, userActivated) {
+    const windowName = String(Math.random());
+    const form = document.createElement('form');
+    const submit = document.createElement('input');
+    submit.setAttribute('type', 'submit');
+    form.appendChild(submit);
+    const win = open('about:blank', windowName);
+    form.setAttribute('method', method);
+    form.setAttribute('action', url);
+    form.setAttribute('target', windowName);
+    document.body.appendChild(form);
+
+    // Query parameters must be expressed as form values so that they are sent
+    // with the submission of forms whose method is POST.
+    Array.from(new URL(url, location.origin).searchParams)
+      .forEach(([name, value]) => {
+        const input = document.createElement('input');
+        input.setAttribute('type', 'hidden');
+        input.setAttribute('name', name);
+        input.setAttribute('value', value);
+        form.appendChild(input);
+      });
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.click(submit);
+        } else {
+          submit.click();
+        }
+      })
+      .then(() => {
+        form.remove();
+        win.close();
+      });
+  }
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+    const userActivated = [% 'true' if subtest.userActivated else 'false' %];
+    return induceRequest('[%subtest.method | default("POST")%]', url, userActivated)
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", " - ")%][%subtest.method | default("POST")%][%" with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/header-link.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/header-link.sub.html
new file mode 100644
index 0000000000..2831f221d5
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/header-link.sub.html
@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for HTTP "Link" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, rel, test) {
+    const iframe = document.createElement('iframe');
+
+    iframe.setAttribute(
+      'src',
+      '/fetch/metadata/resources/header-link.py' +
+        `?location=${encodeURIComponent(url)}&rel=${rel}`
+    );
+
+    document.body.appendChild(iframe);
+    test.add_cleanup(() => iframe.remove());
+
+    return new Promise((resolve) => {
+        iframe.onload = iframe.onerror = resolve;
+      });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], {mime: 'text/html'}),
+        '[%subtest.rel%]',
+        t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] rel=[%subtest.rel%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/header-refresh.optional.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/header-refresh.optional.sub.html
new file mode 100644
index 0000000000..ec963d5cc0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/header-refresh.optional.sub.html
@@ -0,0 +1,59 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for HTTP "Refresh" header</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, test) {
+    const win = window.open();
+    test.add_cleanup(() => win.close());
+
+    win.location = `/common/refresh.py?location=${encodeURIComponent(url)}`
+
+    return new Promise((resolve) => {
+      addEventListener('message', (event) => {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+    });
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage(0, '*')</${''}script>`
+  };
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(key, [% subtest.origins %], responseParams), t
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-dynamic.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-dynamic.sub.html
new file mode 100644
index 0000000000..653d3cdec4
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-dynamic.sub.html
@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dynamic ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [% subtest.origins %], { mime: 'application/javascript' }
+    );
+
+    return import(url)
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-static.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-static.sub.html
new file mode 100644
index 0000000000..c8d5f9532a
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/script-module-import-static.sub.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for static ECMAScript module import</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url) {
+    const script = document.createElement('script');
+    script.setAttribute('type', 'module');
+    script.setAttribute(
+      'src',
+      '/fetch/metadata/resources/es-module.sub.js?moduleId=' + encodeURIComponent(url)
+    );
+
+    return new Promise((resolve, reject) => {
+        script.onload = resolve;
+        script.onerror = () => reject('Failed to load script');
+        document.body.appendChild(script);
+      })
+      .then(() => script.remove());
+  }
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        makeRequestURL(
+          key, [% subtest.origins %], { mime: 'application/javascript' }
+        )
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start",  " - ")%]');
+
+  {%- endfor %}
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/serviceworker.https.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/serviceworker.https.sub.html
new file mode 100644
index 0000000000..8284325546
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/serviceworker.https.sub.html
@@ -0,0 +1,72 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<!DOCTYPE html>
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for Service Workers</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(t, url, options, event, clear) {
+    // Register a service worker and check the request header.
+    return navigator.serviceWorker.register(url, options)
+      .then((registration) => {
+        t.add_cleanup(() => registration.unregister());
+        if (event === 'register') {
+          return;
+        }
+        return clear().then(() => registration.update());
+      });
+  }
+
+  {%- for subtest in subtests %}
+  {%- set origin = subtest.origins[0]|default('httpsOrigin') %}
+  {%- if origin == 'httpsOrigin' or not origin %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [% subtest.origins %], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, [%subtest.options | default({}) | tojson%], 'register')
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.options | collection("options")%] - registration');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [% subtest.origins %], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(t, url, [%subtest.options | default({}) | tojson%], 'update', () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.options | collection("options")%] - updating');
+
+  {%- endif %}
+  {%- endfor %}
+  </script>
+</body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/svg-image.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/svg-image.sub.html
new file mode 100644
index 0000000000..52f7806b33
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/svg-image.sub.html
@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for SVG "image" element source</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const params = {
+    body: `
+      <svg xmlns="http://www.w3.org/2000/svg" width="123" height="123">
+        <rect fill="lime" width="123" height="123"/>
+      </svg>
+    `,
+    mime: 'image/svg+xml'
+  };
+
+  function induceRequest(t, url, attributes) {
+    const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
+    svg.setAttributeNS(
+      "http://www.w3.org/2000/xmlns/",
+      "xmlns:xlink",
+      "http://www.w3.org/1999/xlink"
+    );
+    const image = document.createElementNS("http://www.w3.org/2000/svg", "image");
+    image.setAttribute("href", url);
+    svg.appendChild(image);
+
+    for (const [ name, value ] of Object.entries(attributes)) {
+      image.setAttribute(name, value);
+    }
+
+    document.body.appendChild(svg);
+    t.add_cleanup(() => svg.remove());
+
+    return new Promise((resolve, reject) => {
+      image.onload = resolve;
+      image.onerror = reject;
+    });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+
+    return induceRequest(
+        t,
+        makeRequestURL(key, [% subtest.origins %], params),
+        [%subtest.elementAttrs | default({}) | tojson%]
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+      });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%] [%subtest.elementAttrs | collection("attributes")%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/window-history.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/window-history.sub.html
new file mode 100644
index 0000000000..286d019887
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/window-history.sub.html
@@ -0,0 +1,134 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for navigation via the HTML History API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  const whenDone = (win) => {
+    return new Promise((resolve) => {
+      addEventListener('message', function handle(event) {
+        if (event.source === win) {
+          resolve();
+          removeEventListener('message', handle);
+        }
+      });
+    })
+  };
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately behind the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.back`.
+   */
+  function induceBackRequest(url, test, clear) {
+    const win = window.open(url);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(clear)
+      .then(() => win.history.back())
+      .then(() => whenDone(win));
+  }
+
+  /**
+   * Prime the UA's session history such that the location of the request is
+   * immediately ahead of the current entry. Because the location may not be
+   * same-origin with the current browsing context, this must be done via a
+   * true navigation and not, e.g. the `history.pushState` API. The initial
+   * navigation will alter the WPT server's internal state; in order to avoid
+   * false positives, clear that state prior to initiating the second
+   * navigation via `history.forward`.
+   */
+  function induceForwardRequest(url, test, clear) {
+    const win = window.open(messageOpenerUrl);
+
+    test.add_cleanup(() => win.close());
+
+    return whenDone(win)
+      .then(() => win.location = url)
+      .then(() => whenDone(win))
+      .then(clear)
+      .then(() => win.history.go(-2))
+      .then(() => whenDone(win))
+      .then(() => win.history.forward())
+      .then(() => whenDone(win));
+  }
+
+  const messageOpenerUrl = new URL(
+    '/fetch/metadata/resources/message-opener.html', location
+  );
+  // For these tests to function, replacement must *not* be enabled during
+  // navigation. Assignment must therefore take place after the document has
+  // completely loaded [1]. This event is not directly observable, but it is
+  // scheduled as a task immediately following the global object's `load`
+  // event [2]. By queuing a task during the dispatch of the `load` event,
+  // navigation can be consistently triggered without replacement.
+  //
+  // [1] https://html.spec.whatwg.org/multipage/history.html#location-object-setter-navigate
+  // [2] https://html.spec.whatwg.org/multipage/parsing.html#the-end
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>
+      window.addEventListener('load', () => {
+        set`+`Timeout(() => location.assign('${messageOpenerUrl}'));
+      });
+    <`+`/script>`
+  };
+  {%- for subtest in subtests %}
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    return induceBackRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("right", " - ")%]history.back[%subtest.api%][% " with user activation" if subtest.userActivated%]');
+
+  promise_test((t) => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    return induceForwardRequest(url, t, () => retrieve(key))
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("right", " - ")%]history.forward[%subtest.api%][% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/window-location.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/window-location.sub.html
new file mode 100644
index 0000000000..96f3912361
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/window-location.sub.html
@@ -0,0 +1,128 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  {%- if subtests|length > 10 %}
+  <meta name="timeout" content="long">
+  {%- endif %}
+  <title>HTTP headers on request for navigation via the HTML Location API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  {%- if subtests|selectattr('userActivated')|list %}
+  <script src="/resources/testdriver.js"></script>
+  <script src="/resources/testdriver-vendor.js"></script>
+  {%- endif %}
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <body>
+  <script>
+  'use strict';
+
+  function induceRequest(url, navigate, userActivated) {
+    const win = window.open();
+
+    return new Promise((resolve) => {
+        addEventListener('message', function(event) {
+          if (event.source === win) {
+            resolve();
+          }
+        });
+
+        if (userActivated) {
+          test_driver.bless('enable user activation', () => {
+            navigate(win, url);
+          });
+        } else {
+          navigate(win, url);
+        }
+      })
+      .then(() => win.close());
+  }
+
+  const responseParams = {
+    mime: 'text/html',
+    body: `<script>opener.postMessage('done', '*')</${''}script>`
+  };
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    const navigate = (win, path) => {
+      win.location = path;
+    };
+    return induceRequest(url, navigate, [% 'true' if subtest.userActivated else 'false' %])
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", " - ")%]location[% " with user activation" if subtest.userActivated%]');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.href = path;
+    };
+    return induceRequest(url, navigate, [% 'true' if subtest.userActivated else 'false' %])
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", " - ")%]location.href[% " with user activation" if subtest.userActivated%]');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.assign(path);
+    };
+    return induceRequest(url, navigate, [% 'true' if subtest.userActivated else 'false' %])
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", " - ")%]location.assign[% " with user activation" if subtest.userActivated%]');
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(key, [% subtest.origins %], responseParams);
+
+    const navigate = (win, path) => {
+      win.location.replace(path);
+    };
+    return induceRequest(url, navigate, [% 'true' if subtest.userActivated else 'false' %])
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", " - ")%]location.replace[% " with user activation" if subtest.userActivated%]');
+
+  {%- endfor %}
+  </script>
+  </body>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-constructor.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-constructor.sub.html
new file mode 100644
index 0000000000..fede5965d3
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-constructor.sub.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "Worker" constructor</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(url, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key,
+      [% subtest.origins %],
+      { mime: 'application/javascript', body: 'postMessage("")' }
+    );
+
+    return induceRequest(url
+      {%- if subtest.options -%}
+        , [% subtest.options | tojson %]
+      {%- endif -%}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%] - [%subtest.description | pad("end", ", ")%][%subtest.options|collection("options")%]');
+
+  {%- endfor %}
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-importscripts.sub.html b/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-importscripts.sub.html
new file mode 100644
index 0000000000..93e6374d54
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/tools/templates/worker-dedicated-importscripts.sub.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+<!--
+[%provenance%]
+-->
+<html lang="en">
+  <meta charset="utf-8">
+  <title>HTTP headers on request for dedicated worker via the "importScripts" API</title>
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <script src="/fetch/metadata/resources/helper.sub.js"></script>
+  <script type="module">
+  'use strict';
+  function induceRequest(url, options) {
+    const src = `
+      importScripts('${url}');
+      postMessage('done');
+    `;
+    const workerUrl = URL.createObjectURL(
+      new Blob([src], { type: 'application/javascript' })
+    );
+    return new Promise((resolve, reject) => {
+      const worker = new Worker(workerUrl, options);
+      worker.onmessage = resolve;
+      worker.onerror = reject;
+    });
+  }
+
+  {%- for subtest in subtests %}
+
+  promise_test(() => {
+    const key = '{{uuid()}}';
+    const url = makeRequestURL(
+      key, [% subtest.origins %], { mime: 'application/javascript' }
+    );
+
+    return induceRequest(url
+      {%- if subtest.options -%}
+        , [% subtest.options | tojson %]
+      {%- endif -%}
+      )
+      .then(() => retrieve(key))
+      .then((headers) => {
+        {%- if subtest.expected == none %}
+          assert_not_own_property(headers, '[%subtest.headerName%]');
+        {%- else %}
+          assert_own_property(headers, '[%subtest.headerName%]');
+          assert_array_equals(headers['[%subtest.headerName%]'], ['[%subtest.expected%]']);
+        {%- endif %}
+        });
+  }, '[%subtest.headerName%][%subtest.description | pad("start", " - ")%]');
+
+  {%- endfor %}
+  </script>
+</html>
diff --git a/testing/web-platform/tests/fetch/metadata/track.https.sub.html b/testing/web-platform/tests/fetch/metadata/track.https.sub.html
new file mode 100644
index 0000000000..346798fdc0
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/track.https.sub.html
@@ -0,0 +1,119 @@
+<!DOCTYPE html>
+
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body>
+</body>
+<script>
+  let nonce = token();
+
+  function createVideoElement() {
+    let el = document.createElement('video');
+    el.src = "/media/movie_5.mp4";
+    el.setAttribute("controls", "");
+    el.setAttribute("crossorigin", "");
+    return el;
+  }
+
+  function createTrack() {
+    let el = document.createElement("track");
+    el.setAttribute("default", "");
+    el.setAttribute("kind", "captions");
+    el.setAttribute("srclang", "en");
+    return el;
+  }
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "track-same-origin" + nonce;
+      let video = createVideoElement();
+      let el = createTrack();
+      el.src = "https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      el.onload = t.step_func(_ => {
+        expected = {
+          "site": "same-origin",
+          "user": "",
+          "mode": "cors", // Because the `video` element has `crossorigin`
+          "dest": "track"
+        };
+        validate_expectations(key, expected, "Same-Origin track")
+            .then(_ => resolve());
+      });
+      video.appendChild(el);
+      document.body.appendChild(video);
+    });
+  }, "Same-Origin track");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "track-same-site" + nonce;
+      let video = createVideoElement();
+      let el = createTrack();
+      el.src = "https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      el.onload = t.step_func(_ => {
+        expected = {
+          "site": "same-site",
+          "user": "",
+          "mode": "cors", // Because the `video` element has `crossorigin`
+          "dest": "track"
+        };
+        validate_expectations(key, expected, "Same-Site track")
+            .then(resolve)
+            .catch(reject);
+
+      });
+      video.appendChild(el);
+      document.body.appendChild(video);
+    });
+  }, "Same-Site track");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "track-cross-site" + nonce;
+      let video = createVideoElement();
+      let el = createTrack();
+      el.src = "https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      el.onload = t.step_func(_ => {
+        expected = {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors", // Because the `video` element has `crossorigin`
+          "dest": "track"
+        };
+        validate_expectations(key, expected,"Cross-Site track")
+            .then(resolve)
+            .catch(reject);
+      });
+      video.appendChild(el);
+      document.body.appendChild(video);
+    });
+  }, "Cross-Site track");
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "track-same-origin-cors" + nonce;
+      let video = createVideoElement();
+
+      // Unset `crossorigin` to change the CORS mode:
+      video.crossOrigin = undefined;
+
+      let el = createTrack();
+      el.src = "https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/record-header.py?file=" + key;
+      el.onload = t.step_func(_ => {
+        expected = {
+          "site":"same-origin",
+          "user":"",
+          "mode": "same-origin",
+          "dest": "track"
+        };
+        validate_expectations(key, expected, "Same-Origin, CORS track")
+            .then(_ => resolve());
+      });
+      video.appendChild(el);
+      document.body.appendChild(video);
+    });
+  }, "Same-Origin, CORS track");
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/trailing-dot.https.sub.any.js b/testing/web-platform/tests/fetch/metadata/trailing-dot.https.sub.any.js
new file mode 100644
index 0000000000..5e32fc4e7f
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/trailing-dot.https.sub.any.js
@@ -0,0 +1,30 @@
+// META: global=window,worker
+// META: script=/fetch/metadata/resources/helper.js
+
+// Site
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{host}}.:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Fetching a resource from the same origin, but spelled with a trailing dot.");
+}, "Fetching a resource from the same origin, but spelled with a trailing dot.");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[][www]}}.:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Fetching a resource from the same site, but spelled with a trailing dot.");
+}, "Fetching a resource from the same site, but spelled with a trailing dot.");
+
+promise_test(t => {
+  return validate_expectations_custom_url("https://{{hosts[alt][www]}}.:{{ports[https][0]}}/fetch/metadata/resources/echo-as-json.py", {}, {
+          "site": "cross-site",
+          "user": "",
+          "mode": "cors",
+          "dest": "empty"
+        }, "Fetching a resource from a cross-site host, spelled with a trailing dot.");
+}, "Fetching a resource from a cross-site host, spelled with a trailing dot.");
diff --git a/testing/web-platform/tests/fetch/metadata/unload.https.sub.html b/testing/web-platform/tests/fetch/metadata/unload.https.sub.html
new file mode 100644
index 0000000000..bc26048c81
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/unload.https.sub.html
@@ -0,0 +1,64 @@
+<!DOCTYPE html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/resources/testdriver.js></script>
+<script src=/resources/testdriver-vendor.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<body>
+<script>
+  // The test
+  // 1. Creates a same-origin iframe
+  // 2. Adds to the iframe an unload handler that will
+  //    trigger a request to <unload_request_url>/.../record-header.py...
+  // 3. Navigate the iframe to a cross-origin url (to data: url)
+  // 4. Waits until the request goes through
+  // 5. Verifies Sec-Fetch-Site request header of the request.
+  //
+  // This is a regression test for https://crbug.com/986577.
+  function create_test(unload_request_origin, expectations) {
+    async_test(t => {
+      // STEP 1: Create an iframe.
+      let nonce = token();
+      let key = "unload-test-" + nonce;
+      let url = unload_request_origin +
+          "/fetch/metadata/resources/record-header.py?file=" + key;
+      let i = document.createElement('iframe');
+      i.src = 'resources/unload-with-beacon.html';
+      i.onload = () => {
+          // STEP 2: Ask the iframe to add an unload handler.
+          i.contentWindow.postMessage(url, '*');
+      };
+      window.addEventListener('message', e => {
+          // STEP 3: Navigate the iframe away
+          i.contentWindow.location = 'data:text/html,DONE';
+      });
+      document.body.appendChild(i);
+
+      // STEPS 4 and 5: Wait for the beacon to go through and verify
+      // the request headers.
+      function wait_and_verify() {
+          t.step_timeout(() => {
+              fetch("resources/record-header.py?retrieve=true&file=" + key)
+                  .then(response => response.text())
+                  .then(text => t.step(() => {
+                      if (text == 'No header has been recorded') {
+                        wait_and_verify();
+                        return;
+                      }
+                      assert_header_equals(text, expectations);
+                      t.done();
+                  }))
+          }, 200);
+      }
+      wait_and_verify();
+    }, "Fetch from an unload handler");
+  }
+
+  create_test("https://{{host}}:{{ports[https][0]}}", {
+    "site": "same-origin",
+    "user": "",
+    "mode": "no-cors",
+    "dest": "empty"
+  });
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/window-open.https.sub.html b/testing/web-platform/tests/fetch/metadata/window-open.https.sub.html
new file mode 100644
index 0000000000..94ba76a19f
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/window-open.https.sub.html
@@ -0,0 +1,199 @@
+<!DOCTYPE html>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/resources/testdriver.js></script>
+<script src=/resources/testdriver-vendor.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<body>
+<script>
+  // Forced navigations:
+  async_test(t => {
+    let w = window.open("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    window.addEventListener('message', t.step_func(e => {
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "same-origin",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Same-origin window, forced");
+      t.done();
+    }));
+  }, "Same-origin window, forced");
+
+  async_test(t => {
+    let w = window.open("https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    window.addEventListener('message', t.step_func(e => {
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "same-site",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Same-site window, forced");
+      t.done();
+    }));
+  }, "Same-site window, forced");
+
+  async_test(t => {
+    let w = window.open("https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    window.addEventListener('message', t.step_func(e => {
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "cross-site",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Cross-site window, forced");
+      t.done();
+    }));
+  }, "Cross-site window, forced");
+
+  async_test(t => {
+    let w = window.open("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    let messages = 0;
+    window.addEventListener('message', t.step_func(e => {
+      messages++;
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "same-origin",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Same-origin window, forced, reloaded");
+
+      if (messages == 1) {
+        w.location.reload();
+      } else {
+        t.done();
+      }
+    }));
+  }, "Same-origin window, forced, reloaded");
+
+  async_test(t => {
+    let w = window.open("https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    let messages = 0;
+    window.addEventListener('message', t.step_func(e => {
+      messages++;
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "same-site",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Same-site window, forced, reloaded");
+
+      if (messages == 1) {
+        w.location.reload();
+      } else {
+        t.done();
+      }
+    }));
+  }, "Same-site window, forced, reloaded");
+
+  async_test(t => {
+    let w = window.open("https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+    t.add_cleanup(_ => w.close());
+    let messages = 0;
+    window.addEventListener('message', t.step_func(e => {
+      messages++;
+      if (e.source != w)
+        return;
+
+      assert_header_equals(e.data, {
+        "site": "cross-site",
+        "user": "",
+        "mode": "navigate",
+        "dest": "document"
+      }, "Cross-site window, forced, reloaded");
+
+      if (messages == 1) {
+        w.location.reload();
+      } else {
+        t.done();
+      }
+    }));
+  }, "Cross-site window, forced, reloaded");
+
+  // User-activated navigations:
+  async_test(t => {
+    let b = document.createElement('button');
+    b.onclick = t.step_func(_ => {
+      let w = window.open("https://{{host}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+      t.add_cleanup(_ => w.close());
+      window.addEventListener('message', t.step_func(e => {
+        if (e.source != w)
+          return;
+
+        assert_header_equals(e.data, {
+          "site": "same-origin",
+          "user": "?1",
+          "mode": "navigate",
+          "dest": "document"
+        }, "Same-origin window, user-activated");
+        t.done();
+      }));
+    });
+    document.body.appendChild(b);
+    test_driver.click(b);
+  }, "Same-origin window, user-activated");
+
+  async_test(t => {
+    let b = document.createElement('button');
+    b.onclick = t.step_func(_ => {
+      let w = window.open("https://{{hosts[][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+      t.add_cleanup(_ => w.close());
+      window.addEventListener('message', t.step_func(e => {
+        if (e.source != w)
+          return;
+
+        assert_header_equals(e.data, {
+          "site": "same-site",
+          "user": "?1",
+          "mode": "navigate",
+          "dest": "document"
+        }, "Same-site window, user-activated");
+        t.done();
+      }));
+    });
+    document.body.appendChild(b);
+    test_driver.click(b);
+  }, "Same-site window, user-activated");
+
+  async_test(t => {
+    let b = document.createElement('button');
+    b.onclick = t.step_func(_ => {
+      let w = window.open("https://{{hosts[alt][www]}}:{{ports[https][0]}}/fetch/metadata/resources/post-to-owner.py");
+      t.add_cleanup(_ => w.close());
+      window.addEventListener('message', t.step_func(e => {
+        if (e.source != w)
+          return;
+
+        assert_header_equals(e.data, {
+          "site": "cross-site",
+          "user": "?1",
+          "mode": "navigate",
+          "dest": "document"
+        }, "Cross-site window, user-activated");
+        t.done();
+      }));
+    });
+    document.body.appendChild(b);
+    test_driver.click(b);
+  }, "Cross-site window, user-activated");
+</script>
diff --git a/testing/web-platform/tests/fetch/metadata/worker.https.sub.html b/testing/web-platform/tests/fetch/metadata/worker.https.sub.html
new file mode 100644
index 0000000000..20a4fe5416
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/worker.https.sub.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script>
+  let nonce = token();
+
+  promise_test(t => {
+    return new Promise((resolve, reject) => {
+      let key = "worker-same-origin" + nonce;
+      let w = new Worker("/fetch/metadata/resources/record-header.py?file=" + key);
+      w.onmessage = e => {
+        let expected = {"site":"same-origin", "user":"", "mode": "same-origin", "dest": "worker"};
+        validate_expectations(key, expected)
+          .then(_ => resolve())
+          .catch(e => reject(e));
+      };
+    });
+  }, "Same-Origin worker");
+</script>
+<body></body>
diff --git a/testing/web-platform/tests/fetch/metadata/xslt.https.sub.html b/testing/web-platform/tests/fetch/metadata/xslt.https.sub.html
new file mode 100644
index 0000000000..dc72d7b8a6
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/xslt.https.sub.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+
+<link rel="author" href="mtrzos@google.com" title="Maciek Trzos">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/fetch/metadata/resources/helper.js></script>
+<script src=/common/utils.js></script>
+<script>
+  // Open a window with XML document which loads resources via <?xml-stylesheet/> tag
+  let nonce = token();
+  let w = window.open("resources/xslt-test.sub.xml?token=" + nonce);
+  window.addEventListener('message', function(e) {
+    if (e.source != w)
+      return;
+
+    // Only testing same-origin XSLT because same-site and cross-site XSLT is blocked.
+    promise_test(t => {
+      let expected = {"site":"same-origin", "user":"", "mode": "same-origin", "dest": "xslt"};
+      return validate_expectations("xslt-same-origin" + nonce, expected);
+    }, "Same-Origin xslt");
+
+    w.close();
+  });
+
+</script>
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 17:32:43 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 17:32:43 +0000
commit	6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch)
tree	a68f146d7fa01f0134297619fbe7e33db084e0aa /testing/web-platform/tests/fetch/metadata
parent	Initial commit. (diff)
download	thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.tar.xz thunderbird-6bf0a5cb5034a7e684dcc3500e841785237ce2dd.zip