Fender electronics push button knob

I had this baby laying in my basement for a while.
I got it as a trade, and does not have the usual electronics configuration. two jazz pickups.

It appears that the neck volume knob was swapped for a push button. I believe that it volume controls both pick ups and the sound appears to change when button is pushed to parallel-series... although I’m unsure?

The small knob appears to be unchanged as the tone.

The middle one, does not seem to volume control the bridge pick up and iy changes the tone some.

It is a little late to make a video, I’ll try to upload one tomorrow.

penny for your thoughts on what is going on here?