def METHOD_NAME(metadata_file):
    """Populate dictionary with hash-including filenames from the given file."""
    metadata = load_json(tempdir / metadata_file)
    for target, target_data in metadata['signed']['targets'].items():
        for hash_ in target_data['hashes'].values():
            target_path = Path(target)
            target_with_hash = 'targets' / target_path.parent / f'{hash_}.{target_path.name}'
            hashed_target_files.setdefault(target, []).append(str(target_with_hash))