When deja-dup is in environment.systemPackages, Nautilus does not start because of missing deja-dup GSettings schemas. One possible solution is hard-coding the schema path akin to the GNOME extensions. Personally, I like this since it will allow us to get rid of the wrappers, but it makes the expressions less clean and maintainable.

The problem also occurs with other plug-ins and extensions or even other GTK applications so we should converge on a solution.

Eventually, we might want to lobby with GLib crowd for less global system state (or at least a single function so the patches could be simpler).

cc @hedning, @tiramiseb, @yegortimoshenko