/etc/fonts/conf.d/90-fonts-nanum.conf is in fonts-nanum 3.010-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /etc/fonts/conf.d/../conf.avail/90-fonts-nanum.conf
/etc/fonts/conf.d/../conf.avail/90-fonts-nanum.conf