This is a very small and simple addon that show the number of items in the Item Queue as they enter your bags. The Item Queue is the little stack that appears in the bottom right of the screen when you are receiving items too fast or your backpack if full. It can usually hold a maximum of 5 or 20 items depending on where they are coming from.
Most people will have no use for this but there are some people who use the Item Queue and will find it useful.