Absolutely incredible. They seem to have extracted not just level geometry and textures (which I could kind of imagine normalising to some kind of universal 3D scene format), but also animations and shader effects (which I always imagined being much more bespoke to each game/engine).
Also: copyright lawyers will surely be in touch soon?
This has been around for years and AFAIK none of the copyright holders have ever raised an issue, it helps that the developer isn't tempting fate by taking donations or running ads on it.
Copyrights only generally only start getting entertained if money is being made from it. It might be copyright infringement to post brand logo to a forum but it wouldn't be pursued. Make that forum the forums icon and start generating advertising revenue based on that icon and you'll start getting cease and desist letters.
Also: copyright lawyers will surely be in touch soon?