Most of the deep dive chatter has died down but if you just lurk all the meme stock related forums they'll break it down when someone notices something new. And you can likely find some of the old deep dives perma-linked.

https://www.reddit.com/r/Superstonk/new/

https://www.reddit.com/r/ThePPShow/new/

Basically certain financial entities are permitted to create derivative products. Take for example an ETF. It's a product meant to easily allow you to buy and sell a set of other stocks. What happens though is there are delays in actually acquiring the underlying asset, and very little enforcement occurs when those failures occur.

Now once that phantom asset is created, all the other products can be piggy backed off it. So you can then take out an option on the phantom ETF. Or a swap on the option (swaption). Swaps are basically flimsy agreements and have all the same potential fail to delivery failure (i.e. they don't have to have the underlying to enter the contract). Then you have other insanity like single ETFs:

https://www.investopedia.com/single-stock-etf-5667162

The short of it is these products are built on assumption after assumption after assumption, but the whole meme trade is based on the idea that Wall Street is faking their books and they don't have the underlying shares to deliver on all the fancy ETFs/options/swaptions/swaps/futures/crypto they claim to have. The transparency is non-existent. The regulation is fake.