Parts of the XPK codec implementations are derived from Ancient:

    Copyright (c) 2017-2025, Teemu Suutari
    https://github.com/temisu/ancient

Ancient is distributed under the BSD 2-Clause License. Its copyright and
license terms are retained in the relevant source modules.

Historical XFH and XPK source code is used as format documentation and test
oracle material only. It is not included in this distribution.
