They are on the schematic so at some point someone decided to at least label the nets. There's no mention of a second CAN on the product page so it looks like it's not yet supported and I've left them white. Likewise for the fourth USART and I doubt the SPI ability of two of the USARTs will ever be supported, but I think some people may want to use that one day.
BTW, does anyone know if the power jack is a 2.1 or a 2.5mm type?
Rob