/etc/fonts/conf.d/90-fonts-nanum-extra.conf is in fonts-nanum-extra 20140930-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/fontconfig/conf.avail/90-fonts-nanum-extra.conf
/usr/share/fontconfig/conf.avail/90-fonts-nanum-extra.conf