This is one of those 'totally cool' features that I'm always surprised that most people don't know about.
Adobe Premiere Pro has clip keyframes and it also has keyframes for the track.
Two Quick thoughts
These are GREAT for swapping different music in/out (you just use replace - the keyframes are on the track, so music stays ducked!)
But if you make timing changes on your tracks (such as trimming/removing/adding frames) these keyframes won't slide to stay in place.)