Yeah, it’s not exactly a documented feature, I just figured it out by chance. I don’t get why the “sculpt pivot” is apparently a separate thing from the 3D cursor. If you don’t set that transform option, they can be in two separate places o.O
Anyway… another nice thing is that snapping works with it too, so if you enable snapping to volume you can get this:
It snaps to the center of the volume, really nice for finger posing.