We have various search service notifications for changes of engines, defaults and to help with tests.

Are they all still necessary, or should we reduce what we're sending? Should we be sending more or different ones?

We should have a review, if there's easy changes to make, we should do them here, otherwise file follow-up issues for them.

Note: this is related to other notification work that we want to happen, e.g. bug 1575649, bug 1165341 and bug 606886.