What’s this wire for?

[blown motor]

This wire is tucked inside the wire loom immediately behind it. It's on the starter relay. What would it have been for? Somebody obviously capped it off but chose not to remove it even though it does nothing.

[Katfish]

Probably to power something aftermarket in the past.
I've tapped power from that stud too.

[Brads70]

Looks to me it's from the original battery cable?
https://www.rosevillemoparts.com/product/positive-battery-cable-70-72-e-body-slant-6-70-71-b_rb/

[blown motor]

Looks to me it's from the original battery cable?
https://www.rosevillemoparts.com/product/positive-battery-cable-70-72-e-body-slant-6-70-71-b_rb/

Maybe so. The battery is in the trunk and there's like a molded end on the wire, not typical of a wire someone would use just to capture power.