“It is currently meaningless to talk about stability before solving Rust problems.”
Firefox 128 now renders on Haiku, with every page in a serif font. The blocker is a newer Rust release that changed how formally undefined behaviour acts, which breaks the port in various places and forces a rebase of the Haiku patches. There is no package, and building it takes a lot of RAM and CPU cores. The browser works fine, as long as nobody needs to install it.