It is currently its own mercurial repo. Recent changes have made it bearable, but if you can imagine a central config repo that everyone needs to checkin to in order to make changes like load balancer tweaks, dns updates, shard updates to system X, and runtime configs for tier Y there were times when you could spend hours waiting for a push to finish landing. Configerator changes were the only time in my life I have ever found the need to use a sparse git checkout for a specific tree just to get my job done (back when it was a git repo rather than a mercurial one.)
Having configerator be its own repo also meant that it was easy to add linters that were specific to various config file formats as pre-commit hooks and apply those linters to specific chunks of the configerator tree.
