Hi Guix,

There is a build failure with biber 2.12 in current Guix
(commit 7b40d59114e1462d6d8140f325a66b12e91db667). The build
log is attached, it shows that several tests fail.

Note that I tried to update to biber 2.13, which builds without
problems, but I then discovered that it is not compatible with the
texlive version we currently have.

Cheers,
  Konrad.