That is where accessories such as fog lights or what ever are plugged into (Normally Police Bike Stuff)
It has a cap over it from the factory
Be careful with that uncovered like that
There is a battery positive and ground pin in there that if shorted together will let the smoke out of your electrical system
Plus it has High and low beam and a key on power pin
No fuses in any of the circuits in that connector
The fuses on these bikes only protect the lights (Excluding the headlights) and the horn