postinst is in lsb-release 9.20160110.
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  | #!/bin/sh
set -e
case "$1" in
    configure)
        if [ -e /etc/lsb-release ]; then
            MD5SUM=`md5sum /etc/lsb-release | cut -d" " -f1`
            if [ "$MD5SUM" = "b5bfe10d9b02fb4e4a45337d1c4d88ab" ]; then
                rm -f /etc/lsb-release
            fi
        fi
        ;;
esac
 |