The fake puddles in the game which persist in all weathers reflect things that aren’t there and are way too shiny to be realistic. They are especially bothersome in survival mode as you walk past them again and again and again.
So this mod removes them all. It’s a hack really, but it works.
Unfortunately, it looks like Bethesda used them to cover up some seam issues. You won’t notice them unless you are looking for them.