What is the BROWN Alternator Wire for?

[Grandma’s 68]

Can the brown wire from an alternator be hooked up to the ammeter on a 68 c10?

Original wiring diagrams attached.

At the ignition, switch power seems to goes via a brown/white wire to the bulkhead connector where it splits, going externally to the alternator via a brown wire and internally to the ammeter also via a brown wire. Is the brown/white wire a ‘resistance wire’ as mentioned above?

Also at the switch there is another brown wire that eventually disappears into the fuse panel. It’s not clear what happens there. I guess it powers all the other stuff that’s only on when the ignition is on.

I may be reading the circuit all wrong, so any knowledge sharing would be appreciated.

Thanks.