Thanks for the tip on Helvum. That did make understanding what is going on a lot easier.
In 0.5.13 the monitor pops up and shows the routed audio out of the monitor of the built-in analog stereo source that is doing the playback from the app generating the sound to the app needing the monitor audio.
On 0.5.14 the monitor pops up for an instant as the app needing the monitor launches and then it disappears. I can’t see any way to enable it from Helvum or any diag info inthe Helvum window? It looks like it wants to work and then is killed immediately.