Horn button wire (?)

[Laldog]

Despite taking numerous photos before and during disassembly, I can NOT determine the connection point for this blue wire.

Is it a connection for the horn button?
(At this stage of my advancing age, wiring diagrams only add to the confusion...)

2 of the photos show where the wires terminate, but I can't, for the life of me, determine what the connector inside the rubber boot is attached to.

Any help (or a clearer photos) would be extremely helpful and very appreciated.

 

[Stevehose]

That's the "prisma" bulb wire which illuminates the ignition key lock when the parking lights are on

 

[Laldog]

Sure. Like that's a priority.

Thank you very much for the clarity and prompt response.