What is this? it may be RV related, you never know!

Fill spout for heating tank for oil furnace.

If it is, now would be a god time to take out old tank if no longer in service. And I had to pay $800.00 to "de-certify" my old tank. Can't be done legally except by a guy that attends the county class on it and signs off on the de-cert paper work and gives to county to update county tax records. Had to do it to pass home inspection of the new buyers bank. Of course your local might be different. PM me if you want to know more.