In the Technology preview of the 7.0.0 Release notes, there are two items which talk about the same thing, Clustered Singleton MDB and HA Singleton MDB.

One of them should be removed, I think that HA Singleton MDB is the right candidate for removal.

Also the text in Clustered Singleton MDB could use some clarification.It references a "server node" which is, I guess, supposed to mean the currently selected master on which the MDB is active. But the term "server node" is probably not a good one.
Also the part only one node, the server node, is active it implies to me that only one SERVER is active in a cluster, that's a nonsense, this should be talking about the MDB, not a whole server. My suggestion to rewording it:

The clustered singleton MDB is a technical preview feature in JBoss EAP 7. When an MDB is identified as a clustered singleton and deployed in a cluster, it will always be active only on one node at a time. When the server node fails or is shut down, the clustered singleton MDB is activated on a different node and starts consuming messages there.