[anonymouz]

I don't think it violates the GPL, as the GPL doesn't really care about names. You still have every right to fork git, but have to call it a different name. So if you call your fork "treengler" or whatever, you'd be fine. As far as I can see, you could also still say on your website "Treengler is a fork of Git, that adds/modifies/improves... it in the following way, ...".

To me that seems to be compatible with the text as well as the spirit of the GPL. I think a similar discussion came up in the Debian project with the Firefox trademark at some point. Debian is quite picky about what it means for software to be free, and they seem to be fine with derivatives not being allowed to modify Firefox without changing the name. (At least, I think that was the end status of this discussion.)