Sound Siphon makes your Mac’s audio output available as an audio input device. It allows you to send audio from one application to another, where it can be processed, streamed, or recorded. It's as simple as selecting a microphone in your favorite app. Sound Siphon works with Core Audio to provide this capability to all of your audio apps.

Sound Siphon works with Core Audio to provide this capability to all of your audio apps. As such, it easily integrates into any existing audio-production environment.

Features
Capture all of your Mac's audio
Capture specific application audio
Independently adjust the levels of each application
Capture application audio mixed together as stereo audio
Capture discretely with each application's audio in its own channels
Mute captured applications while capturing
Release Notes

Updates: official site does not provide any info about changes in this version

Supported Operation Systems
macOS 10.15 or later