No API docs on React Refresh

I was experiencing how useEffect was re-running with empty dependencies due to HMR (which was expected) on changes, but I saw how re-running did not trigger the useEffect cleanup function. This was unexpected and maybe a bug? I thought I would reference the HMR / Fast Refresh docs to verify the expected behaviour before reporting, but I could not find anything (apart from reactnative.dev) on any React owned sites! All docs/articles I could find were on third party sites.

AFAIK, Fast Refresh is the native (as in built-in) React solution to HMR, so it is part of React. That means it has an API exposed to end users, and I would then expect it to be documented. Searching "HMR" or "Fast Refresh" comes up with nothing when using the docs search feature.

I can only find "implicit docs" on Fast Refresh on the issue tracker (such as these by Dan: https://github.com/facebook/react/issues/21019) or on external articles and none mention how the cleanup callback is supposed to work in Fast Refresh mode.

Comece revisando o material existente sobre Fast Refresh em reactnative.dev, os resultados de busca da documentação do React para “HMR” e “Fast Refresh” e a issue vinculada #21019. Determine o comportamento esperado do callback de cleanup e documente o comportamento público e os conceitos da API do Fast Refresh em uma página de documentação mantida pelo React.