UO.LTargetZ
From OpenEUO
UO.LTargetZ
⇔ Returns the world z-coordinate of the last target used. You can also write to this variable and use it in conjunction with UO.Macro(22) (LastTarget), which will target this position as if it was clicked with the mouse.
Note: UO.LTargetKind must be set to 2 or 3 for UO.Macro(22) to utilize UO.LTargetZ.