When I imported this into LightBurn it comes in at a tick over 14 inches wide and about 9-7/8 tall.
Historically, the xTool D1 wouldn’t accept instructions in inches. It would ignore ‘inches’ and use mm.
It appears that LightBurn sent the size in mm. The G20 command is seen on line 9 of the GCode file.
LightBurn generated a comment in the GCode file in Line 3 that helps us confirm the size.
X axis (bounds) X407.9-X52.1 = 355.8mm or 14.086 inches
Y axis (bounds) Y339.78-Y89.88 = 249.9mm or 9.8386 inches
This matches the size description in LightBurn if I switch from inches to mm.
The switch is the button in the middle next to the sizes.
I drew a box on tool layer T1 with the size of the Bounds from the GCode file 355.8mm x 249.9mm (the T1 tool layer is Orange)
I’ve asked for the LightBurn Project file in the public thread.