Comment 1 for bug 1752656

Note that SRUing debian-archive-keyring to xenial and earlier is hard, because its keyring generation code relies on gpg features that were added after bionic, and avoiding those features would break reproducibility of the generated keyring files and invalidate the signatures by Debian release team members. If we need to do this it's possible the only sensible option would be to smash in the generated files.