Unknown Mozilla dev addon "Looking Glass 1.0.3" on browser

Many people seem to be shocked because Mozilla installed an add-on automatically. In my opinion, it doesn't really matter since the code is coming from Mozilla - they're building the whole browser, so they could introduce functionality anywhere. If someone distrusts their add-ons, why trust their browser at all?

The main question is what behavior is being introduced. I haven't researched deeply, but apparently the add-on does nothing until the user opts-in on studies.

Speaking for myself here, but I'm not concerned that Mozilla might push malware into Firefox installations. I'm concerned about the lack of judgement in pushing an extension with a vague, scary-sounding name and description simply for a cross-marketing tie-in, and I'm worried that it could have damaged the trust ordinary users have in Firefox.