For four years there has been an open bug report for Mozilla Firefox requesting the browser's GTK widget support be updated for GTK4. An independent user/developer has taken it into his own hands and has managed to get Firefox using the GTK4 toolkit up and running on Linux.

The ticket tracking GTK4 for Firefox can be found via [1]the Mozilla Bugzilla . GTK4 changes complicate the Firefox rendering code and it hasn't been a priority for Mozilla or other developers to move Firefox to GTK4 given little upside for end-users.

Over the past two months though an independent user/developer, Jens Persson, has been working on adapting the GTK code within the Firefox codebase to use GTK4. There are some features not yet implemented and other problems still to address, but it's reached the point of becoming functional. After working through some lingering issues, this week Jens Persson got the GTK4-ported Firefox up and running. Yesterday he posted the first working screenshot of the GTK4 build of Firefox onto that bug tracking ticket:

It's a promising milestone though ultimately remains to be seen if/when Mozilla will pursue upstreaming the code or if this will take on a life of its own as an independent/community Firefox build in the interim or anything along those lines.



[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1701123