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).

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.