When Phabricator hosts a repository, the URL used to access that repository contains the 'slug' of the repository, e.g.:
ssh://172.16.198.140/diffusion/K/
So when I clone that repository (unless I tell git to put it in a different directory name, which is kind of a pain), I get a big directory called "K", when I'd rather have it called something like "myproject-kernel".
Given the restrictions on repository slugs, (all upper case), and the fact that I would like to keep them relatively short, means that this isn't currently possible.