Files have extensions as shown - all files viewed from top.

File extensions as standard from EAGLE.

z-avr-lcd-PTH.cmp - Component side (top layer) copper 
z-avr-lcd-PTH.sol - Solder side (bottom layer) copper 
z-avr-lcd-PTH.con - Board outline 
z-avr-lcd-PTH.drd - Drill file (also incorporates drill rack file nowadays) 
z-avr-lcd-PTH.dri - Drill info file (not strictly needed by PCBTrain) 
z-avr-lcd-PTH.drl - Drill rack file (not strictly needed by PCBTrain) 
z-avr-lcd-PTH.gpi - Gerber info file (not strictly needed by PCBTrain) 
z-avr-lcd-PTH.plc - Component side (top layer) silk screen (printing) 
z-avr-lcd-PTH.stc - Component side (top layer) solder stop mask 
z-avr-lcd-PTH.sts - Solder side (bottom layer) solder stop mask 
