I kept getting this annoying message when starting mythtv-setup on my QNAP:
MythFontProperties: Failed to load 'Liberation Sans', got 'FreeSans' instead
Turns out the Liberation Sans font is a freely available one, I downloaded mine from here
I then installed the ttf files into /opt/share/mythtv/fonts, restarted mythtv-setup and no more warnings about the fonts.