It works fine with Firefox for me since some time. But does it really work with all GTK apps? I would have to install some Gnome app to test. Maybe someone els

It works fine with Firefox for me since some time. But does it really work with all GTK apps? I would have to install some Gnome app to test. Maybe someone else could confirm? This would be progress! (Even it uses some parts of Flatpak under the hood, which is less nice). I'm a little bit skeptical as Firefox had to add support for the desktop-portal before it started to work.