http://archive.ubuntu.com/ubuntu/dists/noble/main/installer-amd64/ should not exist

[Steve Langasek]

mantic went out the door without me noticing that http://archive.ubuntu.com/ubuntu/dists/mantic/main/installer-* still exists. The contents are forward-copies of custom upload artifacts from a source package that has not existed in any release since impish (debian-installer). The Launchpad publisher should be fixed to garbage-collect these artifacts instead of copying them forward in perpetuity.

This should be done before we push out a release of yet another LTS including GPL-licensed binary artifacts whose source code is not part of the series in question.

In addition, the http://archive.ubuntu.com/ubuntu/dists/noble/main/debian-installer/ tree should be pruned. We are continuing to generate empty indices for debian-installer, but we have also long since stopped allowing in the archive any of the udeb packages that would be published there.

Allowances should be made for the possibility that we might, under extraordinary but not impossible circumstances, have to re-publish the release pocket for existing stable series where both of these subtrees remain relevant...