Very hard to say what this was, or even if this was a formally constituted test programme. The only thing that I think you can say for sure is that the debrief was probably pretty robust.
Yes, the envelope is fully explored during part 25 aircraft testing - although I'd be very surprised if any flight test team deliberately entered such a severe departure, so close to the terrain.
Basically however, with no detailed narrative, I'd not read much into that video.
G