The build system for Puppy pre Puppy 4.3
https://web.archive.org/web/20060430001404/http://www.puppyos.com/puppy-unleashed.htm
Where unleashed can be downloaded:
https://distro.ibiblio.org/puppylinux/puppy-2_%26_3_%26_4/
Puppy Linux history including info on Unleashed-Core
http://puppylinux.com/history.html