GBR file D code (plot functions).
Selects and controls tools, specify line type, etc.
For more information please see Gerber RS-274X Format User’s Guide.
GBR file G code (general functions).
Specifies how to interpolate and move to the
coordinate locations following the code until changed or until a new layer
is generated (modal).
For more information please see Gerber RS-274X Format User’s Guide.