File Extentions

Eagle
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*.brd  Eagle Board File
*.sch  Eagle Schematic File

Gerber RS-274-X  (All data TOP view Format2.4/inch) 
----------------------
*.u7  Silk             TOP
*.u5  Solder Paste     TOP
*.u1  Solder Stop Mask TOP
*.u2  Copper           TOP
*.u3  Copper           BOTTOM
*.u4  Solder Stop Mask BOTTOM
*.u6  Solder Paste     BOTTOM


Excellon 
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*.drl  Drills File
*.drd  Drill Station Data  (Format2.4/inch)
*.dri  Drill Station Info 

SMD Coords (unit mm)
---------------
*.mnt  Mount data TOP
*.mnb Mount data   BOTTOM