some packages don't list their /etc/default/ file
Some packages don't list their /etc/default/ file as part of the package:
# for i in /etc/default/*; do dpkg -S $i;done
dpkg: /etc/default/alsa not found.
dpkg: /etc/default/exim4 not found.
dpkg: /etc/default/fetchmail not found.
dpkg: /etc/default/hotplug not found.
dpkg: /etc/default/iptables not found.
dpkg: /etc/default/noffle not found.
dpkg: /etc/default/rcS not found.