TrackerNotifier follows by default all the graphs which seems strange with the subscription api
Tracker3 got support for subscribing to specific graphs, but now it seems that by default the empty graph (= all the graphs) is being subscribed to at tracker-bus.vala, and as there is no subscription id available for that, it cannot be unsubscribed either. And thus it doesn't seem useful to add another subscription.
Good side being that it's avoiding crash on named subscription now on 3.1.1, commented on !397 (merged).