def METHOD_NAME(stream: BytesIO):
    with tarfile.open(fileobj=stream, mode="r") as tar:
        info = tar.getmember("backup.json")
        with tar.extractfile(info) as f:
            backup_data = json.load(f)
            backup_data['size'] = float(
                round(len(stream.getbuffer()) / 1024.0 / 1024.0, 2))
            backup_data['version'] = 'dev'
            return backup_data