This contains the actions "Track: Unsolo all tracks", and "Track: Toggle solo for selected tracks". Sighted folk can click the solo button with a modifier combination if they need exclusive solo (sometimes called solo in place), but there aren't dedicated actions for that yet, so this is a workaround. It's useful if you want soloing a track to automatically unsolo tracks that were previously soloed, or if you want to be able to hit solo on a bunch of tracks simultaneously. Also worth knowing that you can use F6 (the standard OSARA keystroke to toggle solo) to add or remove tracks that are currently being soloed after you've used this custom action.