I am currently working on a project and I'm about to get the Gerber files checked by FreeDFM.com. My question is, in my Gerber files, there are a couple that have the extension .C1 and .C2. In FreeDFM.com they want me to specify what these are (Inner copper layers, top layers etc.), but I have no idea what they are.
Any help in determining what these are would be very much appreciated!