Purple wire on ignition switch?

[clintonvillian]

My diagrams show a purple wire coming from the ignition switch going to the brake warning switch.

Where does it attach? There is a spade terminal on the side of the switch?

Or do I just hook it to the threaded rod on the back?

 

[Slowleak]

There is a terminal for it. It’s the pinkish looking wire in this photo.