While working on WFLY-5418, I noticed that non runtime-only operations can be invoked on domain servers under /host=X/server=Y/...
The operation is not listed in read-operation-names, read-resource-description, etc. but invoking it is still possible.
Brian confirmed that this is a bug and the operation should not be executed.

Steps to reproduce:

• remove the runtimeOnly flag in org.jboss.as.ejb3.subsystem.deployment.MessageDrivenBeanResourceDefinition#registerOperations
• deploy the quickstart helloworld-mdb
• the start-delivery (and stop-delivery) operations are not listed in /host=master/server=server-one/deployment=wildfly-helloworld-mdb.war/subsystem=ejb3/message-driven-bean=HelloWorldQueueMDB:read-operation-names
• But the method can be invoked by executing:

  [domain@localhost:9990 /] /host=master/server=server-one/deployment=wildfly-helloworld-mdb.war/subsystem=ejb3/message-driven-bean=HelloWorldQueueMDB:start-delivery ain@localhost:9990 /]
  {
      "outcome" => "success",
      "result" => undefined
  }