Receive Left Position/Label Top

I'm building a "Zebra Terminal" to send commands and receive information from our Zebra Printers. Two pieces of information I'm looking for are: Left Position and Label Top, but I'm not sure what these parameters are called on the machine. I can, of course, change them with ^LS and ^LT but don't know how to get the machine to tell me them.

I've tried: ! U1 getvar ""zpl.left_position" " " ! U1 getvar ""media.left_position" " "  and ! U1 getvar ""device.left_position"" " ' but it doesn't recognize those names.

I know the machine can as the Zebra Web interface shows below. Any help welcome! Thank you!