The USB gooseneck extension consists of a spring-steel helix with an aluminum filler strip to smooth the outside:
A pin vise holds the intact part of the gooseneck.
The filler unwinds easily, but the spring required several bashes with a drift punch to loosen the first coil. The pin vise can’t apply enough grip to immobilize the spring, so you (well, I) bashed more-or-less radially outward, rather than at a tangent; that’s almost as difficult to do as to describe.
After enough bashing to get a grip with sturdy needlenose pliers, the spring unwound in short sections, again applying force radially to avoid turning the gooseneck in the pin vise:
The black helix aimed off to the side seems to be plastic from the USB shell injection-molded around the connector hardware.
Chopping the spring with the tip of a hardened diagonal cutter (don’t do this with a copper-wire dike!) and bashing the tail ends back around the wire core produced a passable result:
The black thing sticking out beyond the spring seems to be the jacket around the wires.
All the conductors are the same diameter, which
isn’t shouldn’t be particularly surprising.