Gruber has a legal [...] right to ask the Common Markdown maintainers to change names. On what grounds? I do not believe the legal situation is that clear-cut.

Gruber has a legal [...] right to ask the Common Markdown maintainers to change names. On what grounds? I do not believe the legal situation is that clear-cut. As far as the code goes, copyright is not involved as they don't use his code. The trademark hasn't been enforced and there are no trade secrets or patents involved. The only legal issue I see involves the format itself. I'm not sure what US laws say about that, but I'd be surprised if there was an issue.