Their fork in question is: https://github.com/weiluntong/ProtonVPN-server-load
My original upstream code is: https://github.com/twenty5151/ProtonVPN-server-load
First, I am aware of the two related questions: Can someone fork my GPL licensed project and re-license it under MIT or BSD?, and Relicensing a fork of a GPL project and source code distribution requirements. However, the situation here is that they have significantly modified the code.
I know that in principle, it is a violation of the GPL. However, upon reviewing their changes, there is very little similarity to my upstream version. In their commit message, they noted that it is "sufficiently derivative", but I think they meant "sufficiently original". Indeed, my original code has three files in total, and their fork has completely removed my code. Their core logic here essentially shares no original code.
Are their claims of "sufficiently original" valid and does that justify the license change? Is it a "derivative work" of the GPL code anymore? How much does the code need to change to become "original work"?
Edit: reading https://softwareengineering.stackexchange.com/questions/81705/rewriting-gpl-code-to-change-license, the structure of the code is different, but two names/lines have been reused verbatim (out of the entire repo):
response = requests.get('https://api.protonmail.ch/vpn/logicals') servers_dict = json.loads(response.text)
I don't think using requests.get on the url or loading its json is copyrightable work, but the names have not been changed, therefore it is still a "derivative work"? Or can it still be considered Fair Use?