Any progress here? I'm also starting app which need to "record what you hear". I have two problems:
1. I'm linux user and here I solved this with "Monitor of Internal Audio Stereo Analog" but I have to do it manually each time when I start recording :/ . Pavucontrol doesn't remember it
2. Didn't test windows yet, but here it is called WASAPI and works on all versions. Seems that PortAudio has support for it so it will also work with UOS?