prerm is in djview4 4.10.6-3.
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  | #! /bin/sh
set -e
case "$1" in
    remove|deconfigure)
	update-alternatives --quiet --remove djview /usr/bin/djview4
	;;
esac
 |