The end of infinality
If you use Archlinux and the infinality bundle from bohoomil's repository: yesterday's update of harfbuzz from 1.3.4-1 to 1.4.1-1 may break important parts of your setup. The reason is that infinality uses an outdated version of freetype2, and at present it seems unlikely whether we will ever see an update:
Reason: Infinality is dead both upstream and with the downstream maintainer bohoomil, and differences with freetype upstream become small as development progresses
For details, see here and here.
Instead of downgrading harfbuzz, I thus reverted to the stock versions of freetype2, fontconfig, and cairo:
pacman -S --asdeps lib32-freetype2 lib-32cairo lib32-fontconfig pacman -S --asdeps freetype2 cairo fontconfig
The first one only applies if you have the 32-bit multilib-packages installed as required, for example, for steam.
I have not yet replaced the fonts nor is there any immediate need to do so. In fact, the current stock freetype2 seems now to offer an equivalent quality of font rendering as the previous freetype2 with the infinality patchset. Excellent!
I've just checked and found that the situation is even worse for Debian: on my mini (running Stretch/Sid), the installed version of freetype2 is 2.4.9 from 2012. Compared to that, the stock version (2.6.3) can almost be called up-to-date...
apt purge fontconfig-infinality apt purge libfreetype-infinality6 apt install libfreetype6