Comment by TheDong

The only person who has standing to say anything is the original author of the code, the holder of the copyright.

It's possible, but very unlikely, the copyright license wasn't actually violated because, for example, the fork could have arranged a separate license.

The best example of this is the Qt Project's code: https://www.qt.io/qt-licensing

You can get it under a GPL license for free. You can pay them money to get it under a Commercial license that would let you modify the code without releasing changes.

So, while I doubt it happened, the person who forked it here could have contacted the original author, the copyright holder, and asked for an exemption from the GPL terms.