I thought it was from the React codebase, but it's differently named there: https://github.com/facebook/react/blob/b2ca3349c27b57b1e9462944cbe4aaaf76783d2b/src/

I thought it was from the React codebase, but it's differently named there: https://github.com/facebook/react/blob/b2ca3349c27b57b1e9462944cbe4aaaf76783d2b/src/React.js#L67 https://github.com/facebook/react/blob/b2ca3349c27b57b1e9462...