The defaults in 10-hinting-slight.conf introduced in version 2.11.95 lead to really bad/different looking fonts on Arch Linux in several applications e.g. terminal.
A lot of people are complaining and having problems with this, see the Arch Linux forum:
Note that the slowness discussed in the second thread is another (seemingly fixed) issue.
Someone there also mentioned this commit as the culprint:
It would be great if this could be reverted to the old behaviour.
That change was to keep consistency between the desktop-aware applications and others since the default hinting on desktop is hintslight.
If it isn't the case for Arch Linux, you should change it to match your desktop value of course. I don't have a plan to change it in fontconfig unless the desktop default in upstream is changed.
for slowness, if it is because of the cache version bump, it won't be happened once you run fc-cache and get caches updated. anyway, please file a separate bug if still persists.
(In reply to Cem Aydin from comment #0)
> Someone there also mentioned this commit as the culprint:
Given it is, it isn't the reason fontconfig is slowness. that is the rendering issue. not our problem.