It means your car's male connector will have the dark blue wire with stripe, and not the brown with yellow stripe.
FYI. There's a 1974 Master Tech filmstrip and booklet about wiring diagrams. It covers the new style of diagrams introduced in 1973.
pdf version here: Browse MTSC by Model Year – 1974 – MyMopar
One topic not covered in that booklet is keeping track of the circuit. It might be covered in the filmstrip, and it was covered in the 1960's version of the booklet. Basically it comes down to tracing or drawing just hte circuit you're interested in. I think that's even more true on these later diagrams.