def coral_parse_version_extra(extra):
    """
    Parse the extra tag with the format of ${PREFIX}${INDEX}, e.g. tag10
    ${INDEX} is a decimal number.
    010 is identical to 10
    """
    string_index = 0
    for string_index in range(len(extra)):
        if not extra[-string_index - 1].isdigit():
            break
        string_index += 1
    if string_index == 0:
        return None, None

    prefix = extra[:-string_index]
    index_str = extra[-string_index:]
    index_number = int(index_str, 10)
    return prefix, index_number