What Facebook uses internally in their monorepo and what they publish to open source for external consumption doesn't have to be the same build tool. Facebook

What Facebook uses internally in their monorepo and what they publish to open source for external consumption doesn't have to be the same build tool. Facebook uses fbshipit (https://github.com/facebook/fbshipit/ https://github.com/facebook/fbshipit/) to take slices of their monorepo and publish them to GitHub.