FrozenImporter. Docs forthcoming. I plan on all finders and loaders (and most likely hooks) to live in imoprtlib.machinery. Utility stuff will end up in importlib.util. Higher-level API stuff will stay on imoprtlib directly (e.g. import_module).
Closes issue 4993. Thanks Antoine Pitrou for the catch.
planned for the package. There are no docs yet, but they are coming once the API for the first new function, importlib.import_module() is finalized.