This feature has as far as I can remember never been discussed, so it is not part of my plans. There are “zoom snapshots” but that is a different thing.
Note that you can duplicate an arrangement with the “new phantom copy” right-click command in the “arrangements & sounds” listbox. The new copy will share the same sounds/sequences from the original arrangement, but further changes you make to the arrangement timeline will not be mirrored in the other arrangement.