def _is_unpacked_egg(path):
    """
    Determine if given path appears to be an unpacked egg.
    """
    return (
        path.lower().endswith('.egg') and
        os.path.isfile(os.path.join(path, 'EGG-INFO', 'PKG-INFO'))
    )

    Determine if given path appears to be an unpacked egg.
    
src/pkg_resources/__init__.py