rewiring engine bay, question on diagram

In that drawing washer pump supply was changed from brown to blue. Why ? beats me.
It was brown in 73 Valiant that had electric wash. Since the ports in the far right bulkhead connector were the only open available ports, there may have been more options available than the bulkhead could hold. Thus a build without electric wash and with some other option, ( a speed sensor placed inline of the speedometer cable for example ) could very well have had a different wire color in that port. Of course the difference would carry over into the dash harness as well.