So given comment 40 indicating part of this bug has been fixed in bug 1828639, and comment 42 indicating the any remaining patches should be sent to debian, it seems to me that the ubuntu-sponsors team does not need to be subscribed to this, as it's unclear what parts, if any of the attached patches still apply. Unsubscribing ubuntu-sponsors.
Whew, this is a long bug.
So given comment 40 indicating part of this bug has been fixed in bug 1828639, and comment 42 indicating the any remaining patches should be sent to debian, it seems to me that the ubuntu-sponsors team does not need to be subscribed to this, as it's unclear what parts, if any of the attached patches still apply. Unsubscribing ubuntu-sponsors.