According to alex4's author, its license (GPLv2 or later) applies only
to the software, not to any of the data. The data don't have a license
specified, and are therefore proprietary. They should either be
replaced (if there is a free replacement) or the package removed.
Source:
Guix contains font-ubuntu, which is licensed under the Ubuntu Font
License v1.0, which has not been approved by the FSF, and is considered
nonfree by Debian and Fedora, according to <
https://en.wikipedia.org/wiki/Ubuntu_(typeface)#Ubuntu_Font_Licence>.
