Oh, I think I see. So it's just an example of the "Folding Line" cuts on the boxes, so that you don't mistakenly think that the punch was poorly done and try to cut those folds apart. Makes sense in a not entirely intuitive sort of way... Thank you for clearing it up.
I was wondering the same thing until I realized they should have put "Folding Line Example" there instead of just "Folding Line."