Actually, it looks like 4 into 4 into 4, with 3 wires set aside. I'm assuming the box with 4 in and 4 out is a taillight converter to combine the separate brake signal and turn signal into a combined signal for trailer use. Apparently, they were using a 7 pin euro plug adapter to 4 for trailer use.

If you're interested in selling the harness, I'm willing to buy it, to get a factory look. I already have a convertor and a 4pin plug, but like I said, interested in the factory look.

@Aj6543

 

The socket behind the RH taillight has 9 wires going to it, including all 7 that are needed for the 7-pin trailer connection. The plug on this harness that plugs into that socket only has 4 wires. That's what I mean by it going 7 -> 4.
Seems pointless to ignore half of the wires, only to pull them in further down the line.