Mystery Wires in Engine Bay

I have an 81 Vette, in which a Tremec 6 speed was transplanted.  While underneath, I found 2 wires that were cut and sitting under it.  THey are dark blue and green, and appear to be original.  Then went up to the top of the firewall, to a connector.  I have looked through wiring diagrams and manuals and it does not look like they went to the old transmission (or anything else I can find).  Any ideas would be appreciated.

We the original transmission auto or manual?

Prolly speed sensor wires to the cruise control. The TCC connector would have tan, grey, and black wires.

The original was a 4-speed manual, no cruise control.

Since it's a manual, I suspect it might be the backup lite switch. Don't know of any other electrical connections to 4-speed.

I agree that is what it sounds like, without a wiring diagram in front of me. I recall the older cars had green and pink? wires

Well, I think that is it.  I just put the car in reverse and checked, and no reverse lights.  Thanks guys!

Thanks again, guys.  I was able to buy a pigtail, hook up the wires, and now I have reverse lights.