that you asked about. This is the connection between the vented loop and the head. Every other year I need to remove the hose and move the head out of the way to replace the joker valves. If I were, that is, when I need to replace the hose to the loop I'll replace both sides. The other end is located under the sink at a diverter valve with a similar arrangement. Once you get the hose out of the way it's easy to deal with the short section because you can cut it off, twist it off or clean it in place. The stain underneath is from a prior installation and not from the connection you see.