How do backlog quotas and the max_unacked_messages namespace settings interact?

How do backlog quotas and the namespace settings max_unacked_messages_per_subscription and max_unacked_messages_per_consumer interact? Backlog quotas are well documented and make sense to me. Those last two not so much; the config reference indicates that they may control whether or not the broker dispatches messages to consumers, where backlog quotas control auto-acknowledgment behavior. Is that accurate?