Seems like it. But just compare how vocal the "we intend to support vimperator-like functionality" message used to be before version 57, and how silent everything has been since.
I honestly don't remember the actual message from Mozilla varying much over the past two years when it comes to Vimperator-needed APIs. But then I don't remember anyone doing much to get things figured out on that front, so a lack of progress is hardly surprising to me.