Snapd appears to mount `/etc/fonts/conf.d`, and an `ls` of it will show all files in the directory. However, if one rules `fc-conflist` and compare it to the same command on the host system, one will see that not all of the files that are loaded on the host system are loaded within the snap.
Since all the files in this directory are symlinks, it turns out the ones that are loaded are in `/etc/fonts/conf.avail`, but the ones that *aren't* loaded are in `/usr/share/fontconfig/conf.avail`. This causes the font matching rules to be subtly different between the host OS and the snap ecosystem. On Lunar, this causes (for instance) the Steam Snap to choose `Free Serif` over `Liberation` fonts, causing the UI to look very incorrect, but also affects other programs in principle.
Edit: This file is definitely allowed (via AppArmor's <abstractions/fonts>, line 24), and attempting to access the directory (or files in it) doesn't produce any denials, but it doesn't appear to exist.
Hi, thanks for raising this. We are already working in a possible solution for that.