back		back	gbr	Back (solder-side) copper
backmask	backmask gbr	Back (solder-side) solder resist
fab		fab 	gbr	Fabrication diagram
front		frnt 	gbr	Front (component-side) copper
frontmask	frntmask gbr	Front (component-side) solder resist
frontsilk	frntsilk gbr	Front (component-side) silk screen
plated-drill 	drill	cnc	NC drill (plated; finished sizes specified)