Online Sources - configuring

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?

[zip]

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.