Serviio

Library/Online Sources has three configuring options at the bottom:-
Feed expiry interval [hours]
Max. number of feed items to retrieve
Preferred online content quality.

What exactly do these do and what are the performance issues?
How are they related to live/audio streams?
How should they be configured?

The "Preferred online content quality" has three options - low/medium/high.
What does this do and what does each quality translate to?

I am using the "high" option.
My control app (BubbleUPnP) is showing the output streams as "MP3 | 320kbps | Stereo" (a couple are Mono) but the native files are not 320kb and in some cases are not MP3 but aacPlus.
Is this linked to the above?
What is happening?

They are the qualities you can switch in MediaBrowser.... I assume UPnP will not use those, you'd always get the Original quality - which is either the native file, or file transcoded to (in your case 320k mp3).
The Feed config values are relevant to feeds (either RSS or a Web Plugin list of items to play), for live streams they are not relevant.

Thanks Zip for the info.
Can I suggest adding the info/clarification to the console page for the future.