Some of the source code files in most current version of FIGlet do not appear to have free software licenses.
The FIGlet website does not have any information about a bug tracker. The website does list a contact email. A message has been sent to that email on 13 Jun 2021 to bring to their attention this issue.
For more information see: <https://lists.gnu.org/archive/html/guix-devel/2021-06/msg00092.html>
A follow up email was sent 16 July 2021.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the page “GNU Free Documentation License”.
The copyright and license notices on this page only apply to the text on this page. Any software or copyright-licenses or other similar notices described in this text has its own copyright notice and license, which can usually be found in the distribution or license text itself.