Wasn't aerobatics, just a steep pull-up and wingover. A reverse-half-cuban would be the closest description, but carefully flown to not overstress or to get too close to zero or negative g. Smoothly done, with slight positive g throughout. Helicopter doesn't know it is inverted, all it knows is what g forces it is experiencing. Not just the realm of the military, though at least that would have some sanction and probably better organized training.
Typing too slow, looks like Crab beat me to it.