bug#42174: GNU Icecat showing Github Icons?

[Leo Prikler]

It appears icecat is either failing to find or failing to scale DejaVu
Sans.  This usually indicates a broken font-config cache, but since
you're on a foreign distro, it may also be, that you need to install
font-dejavu through guix.  Does `fc-list | grep DejaVu` produce the
results you'd expect?