/etc/fonts/conf.d/65-droid-sans-fallback.conf is in fonts-droid 1:4.3-3ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /etc/fonts/conf.d/../conf.avail/65-droid-sans-fallback.conf
/etc/fonts/conf.d/../conf.avail/65-droid-sans-fallback.conf