ZN1300 - What the heck is this black fuse box?

MY ZN has a 3 inch Bakelite 'GE" box spliced into the ground cable. The box holds a 'bus' style fuse except the fuse had been replaced with a small piece of pipe. I'm assuming this is not original. The only reason I can guess that's it there is as a 'poor man's' quick battery disconnect - if so not sure why it's not spliced in to the positive side of the battery - maybe because the ground cable is more accessible?. In in case, I plan to get rid of it.

Does any of this make sense?

Well, I was wrong, the 'fuse box' was on the positive side of the battery. In any case, I yanked it out. Didn't look like an OEM part to me. My guess is somewhere out there, there's a Harley-Ferguson with a critical part missing:

That's a quick fix when there's a bad diode in the voltage rectifier. A bad diode will leak voltage from the negative to the positive side of the battery and cause the battery to go dead. Installing a dicconnect opens the circuit. so the battery doesn't die when the bike is shut off.. So add to your check list to check the rectifier..

Good advice. Thanks Kawboy.