how does a devkit work then?
Exactly how I loving said it works. It's a version of the console with higher specc'd hardware that allows attached USB devices. Why would it be any different from that? You don't make games on the consoles...
but what about the files that were on it? We'll never know for sure of course what those 20 GB's was of, but considering it was made for employees in-house it most likely had some interesting knowledge on it.
There's. No. Files. On. It.
Dev-kits very rarely have any attached storage, the same as the standard console. It's not necessary, as it's expected the end developer will have a device to store their data.
"cunt leakers"
Every time somebody leaks something under NDA, the NDAs get stricter and the things we developers can do get lessened.