Not much to add to what scifidude said .. Peppermint is based on Ubuntu (or more accurately the LXDE spin Lubuntu) not Debian.
(no part of Peppermint is sourced directly from Debian, conversely nearly all of it is sourced directly from the Ubuntu repos)
Sure you could attempt to suggest Ubuntu is based on Debian (so Peppermint by extrapolation), but besides using Debian package management Ubuntu host all their own packages very few of which are 1:1 copies of Debian packages.
Remember, nearly all the code Debian host is not written by them, just packaged by them .. in the same way Ubuntu package/patch/repackage then host it.
Ubuntu also track their own packages for bugs, and release their own security patches independently of Debian.
It'd be hard to define a distro as "based on" another just because it uses the same package management system don't you think ?
The whole "Ubuntu is based on Debian" argument may have once held some water but I'm not sure it still does, as nearly all the packages have diverged.
(including the core package management packages such as dpkg)
But at the end of the day it doesn't matter what anyone's stance on the "is Ubuntu Debian based" question, Peppermint is built from Lubuntu (sourcing Ubuntu packages) so is Ubuntu based.
If you see any statement on this forum by
Kendall .. you should probably presume it to be true and well considered, he is after all not new at this

(grabs a bag of popcorn) 
Thanks for that, gave me a chuckle
