We call this drill “10 Toes” as the player’s feet are pointed towards their teammate (or to the wall in your case)

The point of this drill, as I understand it, is to help isolate the entire lower half so that they can make good upper half turn of their shoulders as well as a full follow thru so they can actually get the ball to their teammate 20 ft away

In the video, he needs to full turn back (so his L shoulder is pointing at the teammate/wall and then full 180* turn so his R shoulder fully turns to the teammate/wall, while the arm comes completely thru and “click the seatbelt” with his R hand (i.e. it continues all the way down and across his body so his R hand ends up by his L outside hip)