Comment 5 for bug 1800945

Adding just the symlink is not good enough for disco+ as one also needs to backport MERGED_USR=yes stanza, and/or MERGED_USR support, depending on how far back one wants to go. Otherwise, older releases will bootstrap disco non-usr-merged.

Hence e.g. bionic's upload is bad. (which by the way was done with https://bugs.launchpad.net/ubuntu/+source/debootstrap/+bug/1773496 as a bugnumber reference)