xobject

The xobject global is set each turn by the grammar matching stage of the game loop. The simplest way to describe it is the second object mentioned (of a possible two) in one command. In “UNLOCK DOOR WITH KEY”, the xobject would be set to the key object.

That said, the xobject global is not read-only so the author can change it manually at any point to work better with other verb routines.