I recently bought a house and have a slight leak under my kitchen sink. Was trying to figure out where it was coming from this morning so I could fix it, when I found something that makes no sense to me.
There is a filtered water dispenser on sink, on the right
which has two drainage lines coming out of it underneath
that feed into the drainage pipe from the dishwasher 
I'm really confused by this. I don't understand why it would need one drainage line, let alone two. What am I missing here?