This is a forked version of React Sortable Tree to work around a version issue in react-dnd. If you're using RST in a top-level package (ie, you don't intend to distribute it on NPM), then you should use an override mechanism such as Yarn resolutions instead.
See the original project here:
https://github.com/frontend-collective/react-sortable-tree
To install this patched version, use:
yarn install fixed-react-sortable-tree
or
npm install fixed-react-sortable-tree