postrm is in apt-listchanges 2.85.13ubuntu2.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | #!/bin/sh
set -e
hook=/etc/apt/apt.conf.d/20listchanges
if [ "$1" = "remove" ]; then
    test -e $hook && mv $hook $hook.disabled
fi
if [ "$1" = "purge" ]; then
    rm -f $hook.disabled
    rm -f /var/lib/apt/listchanges.db
    if which ucf > /dev/null 2>&1; then
        ucf -p /etc/apt/listchanges.conf
    fi
    rm -f /etc/apt/listchanges.conf
fi
# Automatically added by dh_installdebconf
if [ "$1" = purge ] && [ -e /usr/share/debconf/confmodule ]; then
	. /usr/share/debconf/confmodule
	db_purge
fi
# End automatically added section
exit 0
 |