Package: tasksel Version: 3.39 tasksel is currently at Priority: important and thus installed in every installation, including chroots installed via debootstrap. It doesn't seem a useful package to install in chroots though.
It would be nice if d-i would install tasksel (and maybe remove it at the end of the installation again?) so the priority of the tasksel and tasksel-data packages could be downgraded. Ansgar