[PROBLEM] Which I²S audio device is this?

[TheOldPresbyope]

It's trivial to add the UPnP database plugin to the compile. Its just the --enable-upnp setting.

But I don't see any configuration settings for the plugin. and there is also a upnp Neighbor plugin.
https://www.musicpd.org/doc/html/plugins.html

It's not clear to me how this is supposed to work.

Yeah, I noticed that. Let me see what I can make of Jean-Francois' explanation.