I’ve recently created a non-root user on my Manjaro (KDE Plasma) PC. On this second user account, some pages on Firefox use very ugly fonts. When I log in as my main user, fonts in Firefox look fine. Fonts in Chromium on the non-root account also look normal. Here are some screenshots from an particularly ugly looking website (I’m not allowed to post links or images so make sure to remove the spaces):
Firefox as non-root user imgur. com/NJbnALO
Chromium as non-root user: imgur. com/NBClvay
Firefox as main user: imgur. com/17MDq9L
What I tried until now:
Checked KDE’s font settings, both users have the same settings.
moved .config/fontconfig/fonts.conf from main user to new user. (Had no effect so I switched back to default config)
Changed gfx.font_rendering.fontconfig.max_generic_substitutions in about:config to 127.
Copied my font settings in Firefox to the new user. Interestingly, on my main user account, Noto is shown as the default font in Firefox. On the non-root account, default fonts in Firefox are DeJaVu fonts.
None of these have solved the issue yet. Do you have any other suggestions?
If you are on Testing or Unstable, there recently was an update to fontconfig that had this effect on my FF fonts in Manjaro and my EndeavourOS (VM), but strangely, not in my Arch (VM).
The changes were to:
/usr/share/fontconfig/conf.avail/60-latin.conf
If you prefer, you can put it back to the way it was by editing it and change lines 8, 21, and 38 to put the deja vu version first in the lists again.
Try to copy your whole ~/.mozilla folder from user to new user (there is no such thing as non-root user, I mean all your users are non root). See if using your user profile in your new user changes anything.