it's tough to find information about the extra wires in the cable.
the center conductor is probably the safety ground (earth).
one pair of wires would be the "metering" connection which monitors the voltage at the DC output contact pins (remote sensing).
two more wires for PP (proximity pilot) and CP (control pilot) connections.
the remaining wires may be for thermistors that sense the temperature at the plug and within the cable.
another manufacturer uses these connections and color codes. their cable has fewer wires but the blue/brown color code for the large conductors confirms that this cable is for NACS which can handle either AC or DC.