I dipped into alternator wiring a few years ago when the smoke leaked out of my system: your plug looks like the NipponDenso voltage regulator on my alternator. There are many types of voltage regulators out there based on the vehicle and how it's wired.
IIRC your picture looks like a 1 wire output with three spade (L)ight, (I)gnition, (S)ensing connector. Most of which are optional for our cars per my alternator boffin. So If it ain't broke, don't fix it: I wouldn't worry too much over this detail.
If you don't see the terminal labels unscrew the alternator's back cover and research the voltage regulator item #.
p.