911 plug near glove box, 1971, what is it for?

I just found this receiving plug, somewhat behind the glove box, what would it have been used for?
Some accessory?
Mine has nothing in it.
Was it for a speaker?
it has two (or more) factory wires coming out of it (not shown in photo)
it has little electrical connector holes (also not shown in photo)

It is circled in white, it would have received a plug like the one circled in yellow.
Like a 5 or 6 pin plug, or something like that.
Attachment 453284