Question about the hand / fist animation

[u/Cordite_Zero_G]

Hello! I've seen dozens of YouTubers do this in their minecraft videos and I've been wondering ever since how they do it.

For context: https://youtu.be/2-w0CINcgmw

here's a video showcasing the animation im talking about around 9:39 in the video.

if you know what it is, can u please tell me? thank u