After all these years I only just discovered that the wire trace line....well this subie loom off cut Iam using actually has two trace lines!!

 

The only way iI found out was I used a permanent marker to change the white trace to green

to match the wire i am splicing ( learnt this word from Donald Duck cartoons forty years ago!) Wire is the high beam for light bar relay and I like to keep wiring same. I marked the line last night and this morning the green appeared to have soaked in and faded! Then I made the discovery trace should be called traces.

I have noticed that some colors of sharpie marker fade over time.