Here's a pretty good explanation

https://marketrealist.com/p/what-is-cellar-boxing-in-stocks/

But in short, they decide to destroy a particular stock. They sell shares that they don't have, and then when the stock reaches zero and is delisted, they do not have to provide the stocks that they sold but never had in the first place

Imagine you cut a pair of shorts out of a pair of pants, then you throw the shorts away and wear the remaining pant legs.

It's happening constantly there's no enforcement. They have invented all sorts of mechanisms to continue the practice.