It’s the end of your EVAP system and it comes from the carbon canister behind your left side cover. I have removed my evap system, canister and valve and fitted a electrical plug into the loom where the valve was to fool the computer that the valve is still there and working… so it does not throw an error code. Plus blanking off the vacuum line to the inlet manifold and re routing the overflow line from the tank to the back of the bike. Here is the system as removed. It’s not an airbox drain.