It uses <!-- webkit-test-runner [ CSSBasedRubyEnabled=true ] --> but that leaks to other tests on WK1 because the setting affects the global UA sheet. WK2 knows to swap the process.
<rdar://problem/119121706>
Pull request: https://github.com/WebKit/WebKit/pull/21263
Test gardening commit 271468@main (1750bfb07c80): <https://commits.webkit.org/271468@main> Reviewed commits have been landed. Closing PR #21263 and removing active labels.
Nice!