Uh... there's not a _single_ React "maintainer". There's a React _team_, which currently consists of:

- Seb Markbage: general deep thinking and vision, works on Suspense and some of the server rendering

- Andrew Clark: implemented much of the Suspense and Concurrent Mode core

- Dan Abramov: started Create-React-App, wrote the hooks and Concurrent Mode docs, works on various parts of the library and tooling

- Brian Vaughn: rewrote the React DevTools, added the Profiler, recently implemented the upcoming `useMutableSource` hook

- Dominic Gannaway: previously created Inferno, now works on a lot of the upcoming new event system and other optimizations

- Nicolas Gallagher: previously created React Native Web, now also works on the event system

- Luna Ruan: newer to the team, helped implement the `useOpaqueId` hook that just got merged

- Rachel Nabors: currently working on revamping the docs and community outreach

They have a team bio page here:

https://reactjs.org/community/team.html