Comment 0 for bug 506672

i quickly searched the manual and found no mention of Ubuntu being Debian-based
closest i found was this

"These are known as "debs" and are inherited from Ubuntu’s ascendant, Debian."
but that is way later in chapter 5

my suggestion:
some mention in "A Brief History of Ubuntu", in Prologue
maybe
"Using the Debian operating system as a code base, Shuttleworth built Ubuntu. Ubuntu quickly rose to be the most popular Linux distribution, thanks to the financial..."

I'd add it in myself, or submit it or w/e, but no idea how