Pedantically, I only know the regression is in https://github.com/WebKit/WebKit/compare/4d5530a0a6e0e2032592a7496e6845dfc26aa2ed...92da7f55a72e86de7c02c209489ed4366fa3d742, but I'd be amazed if it were any other commit given what 249880@main changes. See https://wpt.fyi/results/css/css-will-change/will-change-fixedpos-cb-003.html?
<rdar://problem/98158595>
Ah, no. This didn't regress: prior to 249880@main, this was just failing due to bug 242214 (WebDriver screenshots being wrong); the only bug here is 225034. *** This bug has been marked as a duplicate of bug 225034 ***