Importlib_resources 5.1 and 5.2 introduced the following changes (more details at https://importlib-resources.readthedocs.io/en/latest/history.html#v5-2-1):

- Added ``simple`` module implementing adapters from a low-level resources reader interface to a ``TraversableResources`` interface.
- Legacy API (``path``, ``contents``, ...) is now supported entirely by the ``.files()`` API with a compatibility shim supplied for resource loaders without that functionality.

Let's incorporate those into the stdlib version.