XML Config for making Farsi/Arabic fonts of a Linux system looks better
Make sure you have Sahel font installed on your system or change Sahel in 10-sahel.conf file to something you like or you have installed on your system.
Copy 10-sahel.conf file to this path. (Create subdirectories as needed):
cp 10-sahel.conf $HOME/.config/fontconfig/conf.d/10-sahel.conf
After copying the config file, you need to rebuild your fontconfig cahce:
fc-cache
Log out and log back in for changes to take effect.