This video will explain "what the driver is". A quick, useful introduction to SWB Audio Capture and will help you make use of it & SWB Audio App better.
1) I mean the thing you see in Prefs | Sound
2) It's a pipe!
3) Explain pipe again, showing prefs
4) Example:
OBS, single input, being SWB Audio Capture as the INPUT
You're seeing the output from iTunes (as I showed earlier), coming into OBS. And THAT is the goal of the driver. To get audio INTO some other app.
Links to more will follow; when I've made them :)