Comment 6 for bug 1309802

https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1242066 is also very similar. Most packages don't have a lot of debconf questions these days, and just use debconf for changed-config-file prompts, but other debconf questions must surely exist in some packages. (I'm not marking either bug as a duplicate of the other, since they're not quite identical)