There are ways to do this already but I believe that this would be a great additive for streamers, but I was unable to find anything accessible by twitch. If there was any way for a streamer to listen to music and not allow the stream to capture a window, say like permissions to see and hear whatever window you have open, like the Main Screen Share. If you are playing a game and would like to listen to YouTube Music, you could have a button on the stream to mute YouTube Music but not the game?