Need Help Identifying Odd Wooden chair with electrodes and wiring in seat

I noticed the blackening on parts of the leather too, but didn't seem to be in the right place to be caused by the electrified parts we see. Post mentions some apparatus (or battery?) the wires must have attached to. Maybe it darkened the leather.

 

Really hard to know how this thing was wired up -- to what and where the current had a path to/through, but my guess was that the metal bit under the strap was part of that path... maybe not intentionally!

 

I think that little metal thing under the leather explains the blackening there. Can the fitting on the loose ends of the wire clip into that? Person who rigged this up would never meet UL standards.

 

No external electricity involved in that. It's a normal occurrence when you combined leather, metal, and age

 

I don't see "age" and "char" as the same thing, but as I said, maybe I'm misreading the pics.