- ie9 is pretty much dead already? - time to put it at rest? - remove stuff like https://github.com/facebook/create-react-app/blob/bb64e31a81eb12d688c14713dce812143688750a/packages/react-app-polyfill/ie9.js and https://github.com/facebook/create-react-app/blob/bb64e31a81eb12d688c14713dce812143688750a/packages/react-app-polyfill/package.json#L27
https://github.com/facebook/create-react-app/blob/bb64e31a81eb12d688c14713dce812143688750a/packages/react-app-polyfill/ie9.js and https://github.com/facebook/create-react-app/blob/bb64e31a81eb12d688c14713dce812143688750a/packages/react-app-polyfill/package.json#L27