Frequently I see in journalctl output: 

<date> <vm> qubes.StartApp+qubes-run-terminal-dom0[..]: xterm: cannot load font "-misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso10646-1"
It's harmless, just log noise. Comes of using xterm on reduced/minimal templates. Here's the simplest way to make it go away (Debian): 
root@template:~# apt install xfonts-base

root@template:~# fc-fache  # (might not be required)