Gerber RS-274x files:
clocks.cmp	Top (component) side foil
clocks.fab	Fab print
clocks.plc	Top silkscreen
clocks.sol	Bottom (solder) side foil
clocks.stc	top side soldermask
clocks.sts	bottom side soldermask

Excellon drill file:
clocks.drd

Ascii files:
clocks.gpi	Aperture file
clocks.dri	drill info file
clocks.drl	ASCII drill rack file

Note: bottom side foil and mask are mirrored
