Shulker item duplication exploit

There's a duplication exploit that has been around since 1.17.
From what I understand it involves breaking a shulker in survival while shift-clicking items out of it.

Here's the source-code of a fabric mod that does exactly this:
https://github.com/Coderx-Gamer/shulker-dupe

 

I tried it in single and multiplayer 1.18.1 and it works flawlessly.