If'n I was local I'd be there quicker than a high school boy on prom night.
Can't say for certain, but I'm about 90% sure that's an electrical isolator...probably for the positive wire going back to the trailer plug, so the system can charge an RV trailer battery. The "hoses" look like electrical cables to me...yeah looks like that fuel hose coming off the filter inlet could be going to it? maybe some kind of fuel/oil heat exchanger? looks more like a electrical style heat sink though.