I have a question regarding the general purpose of the dbus interface:
is it intended only for snap-to-snap dbus connections, or it also should be used if I want to grant my snap access to some other org.foo.bar service present on the session/system bus?
For example, do I use it to grant my snap access to org.gnome.SettingsDaemon.Power.Screen object? As I understand, my snap would be a “consumer” in this context, which means I have to define a plug with dbus interface for it, but there are no respective slot anywhere that I can connect to since the service is not provided by other snap.