There are always situations where you’d want to route the audio from another software, such as YouTube, into Ableton Live. This tutorial explains how you can achieve this on a Mac.
Soundflower is no longer maintained by its developers. They have a new more advanced sound router app called Loopback, but it’s not exactly cheap. There is also another app called BlackHole, which is free and what I use. The setup works analogous to Soundflower, so you can still follow along to the tutorial video to make this work.
Questions and comments are always welcome.