Initialization command

Question

I noticed an item in the Cell > Cell properties menu that I believe was recently added, but I really would not know for sure (8.0.4 / Win here). It was called Initialization Command :

Nothing about this can be found in my documentation center. It doesn't seem to be in the online link :

Any idea what this should do? As far as I can see, its effect is the same as the “Initialize” menu item.