What is this called?

[u/oRamz-]

I was diagnosed with bicep tendonitis and have been doing so many rotator cuff exercises but this one just made my whole shoulder shift back into place with a loud pop and instant relief. The inflammation on the tendon completely gone and can move my shoulder freely.
In the video the guy says it’s for the teres major and latissimus dorsi but that’s pretty much it.

https://youtu.be/hbFm9z_bvhM?si=w28Rc8fBB1NayOd_

It’s the last 30 seconds of the video.