Engine wiring harness question

[sodly]

Can anyone tell me how to remove the wires from this engine harness plug (1966)? This is the plug that plugs into the firewall. How do you remove a wire from it? Do you need to stick something into the plug to release a tang? I have one wire that's developed a bare end that needs to be cleaned up. Probably will have to remove all of them from the plug to fix the one.

Anyone know what style of spade is on these wires that goes into that plug?

By the way, the problem wire is different than the others. It has sort of a metal braided coating, unlike the others that are colored plastic. Anyone know off hand what this wire does? The wiring diagram is unclear. This is a completely stock 327 truck.

Thanks!