Was the connector just hanging out, or was it connected to something?
It was disconnected and laying on the bottom of the boat. Looks like they disconnected whatever it was attached to, removed it, disconnected the brown from the batteries and simply left the connector and wires where they were. All the wires in the second picture were connected to the connector when I found it. I cut them to ease removal. So far, I only know that the brown wire went to the battery compartment, so I assume it was a hot.
Come to think of it, the brown spliced to a black under the motor, so I think it was probably the thick black in the picture. So...it looks like they needlessly made the run so long they ran out of black wire and simply continued with brown for a hot, when there was another brown wire in the harness.
Imagine trying to troubleshoot the unit (whatever it was), seeing a brown and black at the harness, a brown at the batteries, and no black!
BTW, the unnecessary splice was in the bilge under the motor! Could you pick a worse place to splice a wire? I'm no ace electrician and hate to criticize others "work", but c'mon!
It will be interesting to see where the other wires lead.