GTK 4 applications use accessibility bus directly and will try to connect to it every time a widget is created: https://gitlab.gnome.org/GNOME/gtk/-/issues/4831 This will make GTK 4 apps (e.g. newly ported Nautilus) grind to a halt on systems that do not have AT-SPI service installed. Let’s explicitly disable accessibility support with an environment variable when the AT-SPI service is not enabled to avoid that. Just like we do for ATK-based applications with `NO_AT_BRIDGE`. Fixes: https://github.com/NixOS/nixpkgs/issues/197188