postinst is in php-horde-lz4 1.0.10-2ubuntu1.
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 | #!/bin/sh
set -e
# Automatically added by dh_php/UNDECLARED
for conf in horde_lz4; do
    dpkg-maintscript-helper rm_conffile /etc/php/mods-available/${conf}.ini -- "$@"
done
if [ -e /usr/lib/php/php-maintscript-helper ] ; then
    . /usr/lib/php/php-maintscript-helper
    for version in 7.2 ; do
        for conf in horde_lz4 ; do
            php_invoke enmod $version ALL $conf || exit 1
	done
    done
else
    for conf in horde_lz4 ; do
        phpenmod $conf
    done
fi
# End automatically added section
 |