Per suggestion of a friend, I installed his #Debian package called Dbus Broker into a machine running Bullseye, for improved perrformance, especially re: orca and web browsers. He also included a new build of atspi2-core, with dbus broker support. Indications are that the dbus broker service is running, and communication between atspi2-core and the broker are happening. I notice no performance changes, yet. More testing needs be done.