It is described on the same page you linked above.
Still to be considered experimental, but yes the target is a MOD unit acting as USB sound card.
(This is sadly broken in v1.10.1 due to a small mishap on my side, tested on Dwarf but forgot to check Duo/Duo X.)
If you want to try it out, I can give you a fixed v1.10.1 build.
So I had a look at this. The netmanager issue on Duo is not possible to fix without breakage.
Either it works for units with old 3.4 kernel, or works for units with 5.4 kernel, can’t be both at the same time.
Since this is clearly labelled EXPERIMENTAL in the settings, we will leave it as-is.
You can run these commands on a 5.4 kernel Duo to manually fix things: (but will revert and have to be re-run on next update)
mount / -o remount,rw
systemctl enable jack-netmanager.service
mount / -o remount,ro