That's an optional step for JSX cross-compilation. It's a language plugin; nothing really to do with frameworks or libraries.
What they've added is wrapping your code in more memoization functions, basically. All stuff that doesn't fundamentally transform the code, aside from inserting more `useMemo` and the like.
The JSX macro - which is itself already optional but everyone uses it - is just that, a handy macro with implementations available in every common bundler and transpiler out there.