My understanding is that they used c2rust, and then told the LLM/Agents to make the code more idiomatic rust, while also using the PG test suite as a feedback mechanism. This is almost certainly a derived work (and thus a fork, and should thus have the original license and copyright preserved).

For example, if I compiled PG into x86-64 assembly, and then decompiled it into C (via, say, IDA), and then polished that decompiled C code into very readable C code, it is still a derived work. For some reason, people think that if you include an LLM or Agent, copyright can be ignored, and plagiarism is now no longer possible.

It is similar to the crypto-folks thinking that if you use crypto, you no longer have to pay taxes, because the internet/computers make all inconvenient realities go away.

Honestly, such flagrant and arrogant copyright violations make it hard for me to take the project seriously, because it seems like a desperate stunt for attention (which itself may be a solid business move, but that is besides the point).

Put differently, if one were to fork pgrust, strip away the new license and copyright, and restore the original PG license and copyright (while also adding malisper+team to that copyright), they would face no legal consequences at all. In fact, they would probably be a less legal risk than the pgrust team.