NAME
LAYER
pcbname.GTL
Top Copper
pcbname.GTS
Top Soldermask
pcbname.GTO
Top Silkscreen
pcbname.GBL
Bottom copper
pcbname.GBS
Bottom Soldermask
pcbname.GBO
Bottom Silkscreen
pcbname.TXT
Drills
pcbname.GKO
Board Outline