/usr/sbin/cracklib-format is in cracklib-runtime 2.9.2-1build2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 | #!/bin/sh
#
# This preprocesses a set of word lists into a suitable form for input
# into cracklib-packer
#
gzip -cdf "$@" |
grep -v '^\(#\|$\)' |
tr '[A-Z]' '[a-z]' |
tr -cd '\012[a-z][0-9]' |
sort -u
|