postinst is in php5-sasl 0.1.0-3build2.
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  | #!/bin/sh
set -e
# Automatically added by dh_php5
if [ -e /usr/share/php5/php5-maintscript-helper ] ; then
    . /usr/share/php5/php5-maintscript-helper
    for conf in sasl  ; do
        php5_invoke enmod ALL $conf || exit $?
    done
fi
# End automatically added section
 |