/!\ The utnubu team has stopped to exist many years ago; cooperation between Debian and Ubuntu is pervasive these days.

/!\ If you would like to get packages from Ubuntu into Debian, you can do so via the relevant teams, sponsors or direct uploads if you are a Debian member.

Utnubu is Ubuntu spelled backwards. One of Ubuntu's activities is frequently redistributing packages originally from Debian to Ubuntu's users. Well, Utnubu is about the reverse, copying packages from Ubuntu to Debian.

Links, background info