postrm is in bootlogd 2.88dsf-41ubuntu6.
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
case "$1" in
    purge)
	#
	# Remove log files
	#
	rm -f /var/log/boot
	# Remove rc symlinks in the reverse dependency order they were
	# inserted
        update-rc.d stop-bootlogd        remove >/dev/null || exit $?
        update-rc.d stop-bootlogd-single remove >/dev/null || exit $?
        update-rc.d bootlogd             remove >/dev/null || exit $?
        ;;
esac
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