Currently they traverse from the main frame, which may in a different process with site isolation.
<rdar://problem/116374168>
Pull request: https://github.com/WebKit/WebKit/pull/18523
Committed 268798@main (86a15eb9f4a9): <https://commits.webkit.org/268798@main> Reviewed commits have been landed. Closing PR #18523 and removing active labels.