A printed circuit board (PCB) includes a stack of core layers disposed one over another, and electrically conductive interconnects extending vertically in the stack. Each of the core layers includes a substrate having opposite major surfaces, an electrically conductive active trace extending along at least one of the major surfaces, and an indicium. The stack also has an exposed edge where the indicia of the layers are together revealed. The indicia provide identifying and/or fiducial information about the PCB.