Question about overriding existing clips

Hey there!

I've been using timeline in my project for many different things and I think it's a great tool, and the ability to extend it using user-generated playable clips is awesome.
But I just thought about some feature I might need on my specific game to reduce a lot of work from my workflow involving the animation clips, so I decided to go ahead and override that animation clip in order to extend it to my use-case.
But it seems that this class is for some reason sealed, and therefore I cannot override it.

Why is that? I think user generated extensions to this specific track type can create some really creative stuff because of how heavily it is integrated with the editor.

Also, am I just wrong and there is a way to override this track type?

Also, keep up the good work, amazing new features are always improving my workflow and I can't wait to see what using Unity will be like even just a few years from now