Testcase: javascript:alert('manifest' in document.documentElement ? 'FAIL' : 'PASS') The spec intentionally omits the 'manifest' IDL attribute on <html> because "Changing the attribute dynamically thus has no effect (and thus, no DOM API is provided for this attribute)." http://www.whatwg.org/specs/web-apps/current-work/complete/semantics.html#htmlhtmlelement
Presumably the spec used to have it...
I changed the test case from Comment 0 into JSFiddle: Link - https://jsfiddle.net/p9m47wy8/show It is reproducible and still showing "FAIL" in Safari 15.6 on macOS 12.5 while all other browsers (Chrome Canary 106 and Firefox Nightly 105) show "PASS". Just wanted to share updated testing results. Thanks!
Pull request: https://github.com/WebKit/WebKit/pull/2951
Committed 253053@main (332debf04f06): <https://commits.webkit.org/253053@main> Reviewed commits have been landed. Closing PR #2951 and removing active labels.
<rdar://problem/98007679>