Where Did This Tiny Spring Come From ('65 Barracuda)?

It's maybe 1/4" in diameter, or 5/16" at the most.

Checked the parking brake handle; it has it's spring and very heavy duty compared to the spring in question.

Checking the Carter AFB, the primary throttle plate has a built in spring (still there) that weakly closes the primary throttle. The return spring that connects to the hook on the intake manifold is here, much longer and stronger than the spring in question.

I haven't found the A/T kick down/pressure linkage yet, that remains a possibility.