Expanding on what mikemcquaid and mtodd said, essentially it's been replaced with bash and a sprinkling of ruby (Mostly for templating, IIRC).

Me saying "replaced" is a bit of a misnomer though because the way we create, maintain, and configure Enterprise is totally different now making Chef and Puppet overkill for our uses. We no longer try to maintain the state of the entire system throughout upgrades instead favoring placing a complete system (built using mostly bash and again a bit of ruby).

Since we only now need to change a few configs we can do that using bash and ruby. This resulted in huge speed ups when reconfiguring Enterprise.

It's hard to over emphasize how much of the underlying way that Enterprise was put together changed and was improved with this release. Everything from developing on it, to releasing it, to deploying it, to upgrading it has all been shifted.

Huge respect to the infrastructure folks that made this happen (certainly made my life easier as a dev!).

We're using Puppet on github.com but GitHub Enterprise didn't warrant the use of either so: nothing.