I really feel like that is part of the convertible setup, but I cannot say that with certainty. Maybe you could watch a video on replacing the top and see if you spot that part anywhere?
What is this connector for? Its below the left rear seat and can't find any counterpart connector around. I guess it was never used?
'94 GT Convertible
Regarding that first crochet needle two-loop thing at the beginning of your thread, can you Google a picture of it and maybe get a result? Long shot but worth the 2 seconds it takes.
But so far, I'd guess a convertible part like Iwarrioer1016 said.