postinst is in libpython2.7-minimal 2.7.11-7ubuntu1.
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 | #! /bin/sh
set -e
if [ ! -f /etc/python2.7/sitecustomize.py ]; then
    cat <<-EOF
	# Empty sitecustomize.py to avoid a dangling symlink
EOF
fi
if [ "$1" = configure ]; then
    rm -f /etc/python2.7/cert-verification.conf 
fi
exit 0
 |