Linux

This is getting downvoted but honestly, "why?" This is a good question. Too few people understand why GPL licensing is important.

A working "Linux" fork with a "do whatever you want we don't care" license means that people can just take the code without ever attributing credit or contributing back. They can make their own proprietary kernels from this and dispense from the free and open source part. They would also be free to commercialize the software without restrictions and impunity. As it stands GPL3 in particular is restrictive enough to be considered "bad for business" but it's also the only license that actually protects free software in court