As of Firefox 143 we removed MozAppearance from the style properties object.
Bug to remove: https://bugzilla.mozilla.org/show_bug.cgi?id=1977489 This has always been Gecko specific and been used by old websites and libraries to detect Firefox. Removing it fixed a few web compatibility issues as seen in the dependency tree. The actual CSS property `-moz-appearance` is still supported for best compatibility. (The actual change has made in 2025-07-22, so this is a late notice, sorry. But still in the same cycle!) -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/mozilla.org/d/msgid/dev-platform/157dcb21-b543-4fa1-a8fd-b0445f6ab08cn%40mozilla.org.
