Comment by testdelacc1

I read a lot about this when Rust was considering adopting a trademark policy. The main use cases for enforcing the trademark were

- preventing someone who hardforked the project from creating an incompatible language while using the same name.

- preventing someone from distributing malware while still using the same name.

Because if you notice, neither of these clash with the MIT license that many languages use. You need to enforce your trademark to stop this kind of behaviour.

Zigbook can argue that they aren’t causing any confusion between themselves and the Zig language. The Zig foundation could argue that the name implies an endorsement by the project and they should call themselves The Unofficial Zig Book instead. I don’t know which way it goes.