So what is it? Red "light"?

^^Exactly^^ These work just like the door switch on the dome light. Switch is on/off to ground, lamp is fully insulated from ground. One wire from a key-switched source to the light, a second wire from the lamp to the parking brake switch.

Or this...

What's the technical term for this wiring technique?

Not a lunchbreak effort.

Added to "the list"

I did get the nuts out....:BangHead:

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