rmgen2 is a convenience library over rmgen which handles more details implicitly and generalizes parameters. At the time it was introduced, it also contained some other generation code such as bluffs and whatnot. However, libraries of libraries usually suggest an anti pattern. #4947 and several commits later, most additions brought by rmgen2 has been ported over to rmgen1, and by now, its mostly just proxies. Maps written without those proxies ought to not have a dependency on it, and maps written with those are preferred to be without them. rmgen itself should have a usable enough interface that could be used without a wrapper around it.