ZWPPSTOCK : this report shows the projected stock for materials.  Could be finished products, intermediates, raw or pack materials.  having the visibility of the projected stock, with a quick overview, you can detect if there is a shortage issue in the future  for a material.  A direct link to MD04 allows you to quickly have a look on where the problem is coming from.  Some filters are available to finetune your selection and the elements you want to be displayed.