The 3.8.x release stream reached end-of-life; see dev@ discussion:
https://lists.apache.org/thread/2t99pftq06j25rq7j3h1l0z5xsn57z6b

This tag preserves the branch's final state (last real content is the
maven-3.8.9 release plus the automatic next-development-iteration bump)
before the branch itself is removed.