We don't have any really formal relationship but we are friends with a lot of the people who work on React and React Native there. They are just down the road so we sometimes get together and talk about things. We sometimes ask them for help when we upstream a PR and need to get that into RN (thanks to Hector in particular!!!) We've collaborated on things in the past like create-react-native-app and yarn and I think we'll collaborate a lot more going forward.