At ReactConf 2018 (October 25-26, 2018) at Henderson, Nevada, I spoke about React Native's new architecture covering the JavaScript interface (JSI), UI re-architecture (called Fabric) and the new native module system (called TurboModules).
I dove into more details and added a little bit of "Star Wars fun" on the same topic at React Next (Nov 4, 2018) at Tel Aviv, Israel.