I think there were hints of that already in S2, but I don't recall it was mentioned explicitly so far. You could piece that out from the show if you knew what to look for. The books have been more explicit about it earlier in the storyline.
Well, it has some other means of abusing spacetime beyond FTL communications, but your description is mostly accurate. It's a sophisticated piece of nanotech built by someone with much better grasp of (in-universe) physics than humans have.
