On my Rhone Valeo alternator the yellow sense wire goes via an inline fuse to the alternator regulator. So perhaps the spade connector you see likewise connects to a fuse holder which in turn goes to the regulator or direct to a blade connector under the regulator cover.
See attachment for diagram of this.
I agree it’s better to have it connected to the house battery output stud on the split charger.
Also you could just Googling (other search engines are available) wiring diagram for your make of alternator.
The membership association for owners of Dufour Yachts