> If it's not clean room, then there's probably copyright violations.

This is the law in the United States. From the links given in the readme file the authors are probably from Russia.

As a non-US citizen, I can't wait to see a world where a whole IT industry will exist without caring much about merchandability in the US.

Copyright extends beyond the US, due to certain treaties.

But yes, Antigua's IT industry could get very interesting if they get to keep the whole copyright haven thing going.

Copyright applies in Russia too. There are bits and pieces straight "reused" from other software - by his own admission.

So his claim that he is a sole copyright owner is patently false - this code could be trivially attacked as a derivative work. No sane person would touch it by a 10 foot pole.

I don't know much about Russian copyright law, but at least the idea of the German copyright law (Urheberrechtsgesetz) is very different from the US one. Here the central concept is the "Urheberschaft" (authorship; this implies that you have to be acknowledged as author) which cannot be sold, donated, refused etc. (as opposed to in the copyright law). The only thing that can be sold are the Nutzungsrechte (rights of use), which allow to redistribute the work and make money from it. Thus in Germany there exists for example no analogue to public domain work: Since Urheberschaft cannot be donated, one simply cannot put works under public domain, see for example https://www.sqlite.org/copyright.html