Kind of a niche thing to comment on, but this release lands a commit I made that enables XDG desktop portals support in Firefox. If you’re on KDE Plasma, you can run Firefox with the environment variable GTK_USE_PORTAL=1 set and it will use KDE file selection dialogs.
firefox is already patched with the suse plasma integration patches (which enable things like plasma file dialog, opening dolphin for downloads etc) so I’m not sure what this does above that?