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 0000000000000..70d7faca2b417
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors-frame.html
@@ -0,0 +1,24 @@
+<
+!
+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 0000000000000..148442efaa3fc
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/resources/serviceworker-accessors.sw.js
@@ -0,0 +1,143 @@
+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/serviceworker-accessors.https.sub.html b/testing/web-platform/tests/fetch/metadata/serviceworker-accessors.https.sub.html
new file mode 100644
index 0000000000000..04a7cefa7124c
--- /dev/null
+++ b/testing/web-platform/tests/fetch/metadata/serviceworker-accessors.https.sub.html
@@ -0,0 +1,392 @@
+<
+!
+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
+>