305422 2026-01-13 13:55:48 -0800 tiktok.com: [macOS] Please upgrade to the latest version of your browser - message on upload 2026-01-14 12:20:49 -0800 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 bfulgham bfulgham webkit-bug-importer oldest_to_newest 2171557 0 bfulgham 2026-01-13 13:55:48 -0800 We have the unfortunate architecture of two separate “Custom User Agent” values governing page loads and the Navigator API (see Bug 305420). One is called customUserAgent, and was the field we populated when fixing the iOS version of this bug. There is also a customUserAgentAsSiteSpecificQuirks field, which happens to be used in the macOS case. Because this value was present, the Navigator API was using it in preference to the customUserAgent field set in WebsitePolicies. This caused my attempted fix in Bug 291113 to start failing as soon as a quirks-level custom URL scheme was set on macOS. For now, I’m just applying the same fix to customUserAgentAsSiteSpecificQuirks (if it exists) so that whichever flavor of custom URL is in place, it is tweaked with the necessary like Chrome/136 string. I will see if we can streamline and simplify the handling of custom User Agent separately in Bug 305420. 2171558 1 bfulgham 2026-01-13 13:56:01 -0800 rdar://166837052 2171569 2 bfulgham 2026-01-13 14:34:31 -0800 Pull request: https://github.com/WebKit/WebKit/pull/56522 2171903 3 ews-feeder 2026-01-14 12:20:47 -0800 Committed 305598@main (f4cfd452ee0a): <https://commits.webkit.org/305598@main> Reviewed commits have been landed. Closing PR #56522 and removing active labels.