>>Nodes names won't be on the CAN Transceiver datasheet.
I know this - I mentioned it because your including it wasn't really useful in your original post. But, a schematic, or portion of it, would have been much better.
I suspect that the designer of the PCB simply provided 2 connectors for attaching the CANbus connection so that wire splices on one connector to continue the bus connections to other nodes in the system would not be necessary. In this way, the connections could be possibly more reliable, or waterproof, or something.
I am having to infer all this from pure guesses however, as you have not provided any more information about the board or how or where it is used.