fast/borders/border-radius-on-html.html ref test doesn't seem to pass Safari, Chrome and Firefox render the test case and expected case differently. However, WebKitTestRunner doesn't catch, it passes because it's using different setting. bug#243422 is going to match WebKitTestRunner setting.
253132@main fixed the WebKitTestRunner problem. The test is failing now. https://results.webkit.org/?suite=layout-tests&test=fast%2Fborders%2Fborder-radius-on-html.html
<rdar://problem/98339384>
Firefox, Chrome and Safari all show solid green with this testcase (no rounded corners visible). However, if the WKWebView is set to be transparent, I would expect the rounded corners to show up.