+ Ditch using arguments to super(). + Ditch subclassing from object directly. + Move directory check out of chaining path hook to file path hook/finder. + Rename some classes to better reflect they are finders, not importers.
importlib.test.support to importlib.test.source.util.
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.