I’m currently trying to get the app menu patches provided by Ubuntu for Firefox to work on a fork. The required appmenu-gtk3-module has already been packaged and works for every application but Firefox. They have been built from efforts already done here.
The derivation of firedragon (the name of my fork) can be found here, it basically takes Librewolf patches and adds some more patches to enable advanced KDE / app menu integration:
This works very well on Archlinux, here an app menu is provided to KDE. It does not, however, on NixOS.
Already tried some things, such as adding gsettings-desktop-schemas to buildInputs as seen here, but that didn’t help either.
Does anyone have an idea what I might be missing in order to make it work?