[optymizer]

I learnt Sapling while at Meta. I was skeptical when someone said "it's better than git" but then I used it and I will in turn now say that it's indeed better than git. At the very least it doesn't yell at you for not being on a branch and losing code, but it has easy commands for working with a source tree and working with diff stacks. I haven't used it outside Meta's infrastructure though.