Any 70 wiring experts?

[Midlife]

I just refurbished a 70 underdash harness, and couldn't find any documentation on two wires.

The first is a large white female bullet plug on the engine side of the firewall.  It is tied into the fuse box, but I can't figure out what it connects to on the engine side.  Is it for emissions control?

The second wire is a gray wire that ties together a small flat green 3 pin connector and a 2 pin red connector under the dash.  Part of these connectors go to the key reminder/door ajar buzzer system.