Probably just that nobody has sat down and done it. Maybe that could be you... :)
https://github.com/exercism/x-api/blob/master/CONTRIBUTING.m...
https://github.com/exercism/x-api/blob/master/CONTRIBUTING.m...
I was wondering why no C because that is one I could use, and would like, the practice on. So for everyone else's sake, I won't.