postinst is in kdesudo 3.4.2.4-1ubuntu1.
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 | #! /bin/sh -e
case "$1" in
    configure)
        update-alternatives --install /usr/lib/kde4/libexec/kdesu kdesu /usr/bin/kdesudo 100
    ;;
    abort-upgrade|abort-remove|abort-deconfigure)
    ;;
    *)
        echo "postinst called with unknown argument \`$1'" >&2
        exit 1
    ;;
esac
exit 0
 |