Resampling is a neat trick in ableton live where you can capture the output of the master track and reinsert it into your project for additional processing. It’s a nice workaround, instead of flattening a track.
To resample, insert a new audio track, then change its audio from section to “resampling,” then arm the track, then record audio on the track. Once recorded, you will have audio on a single clip from all currently playing tracks that passed through the master. You can solo individual tracks to capture specific elements as well.