EXTMAX system variable

Function Description:

The EXTMAX system variable is used to store the value of right-top corner point in the drawing extents.
(Read-Only)

Type : 3D point
Saved in : Drawing
Initial value : Unknown

If some new objects created outside of limits, users could use "All" or "Extent" option of ZOOM command to scale objects to new extents.
The EXTMAX system variable value is the world coordinate value in current space.