Biscuit packaging bags are folded in half on both sides of the packaging machine, and heated and stitched (the extra part on the back of the package, commonly known as "middle seam") and the end heated and stitched (two serrated cuts, commonly known as "end seam").
The "middle seam" part is not the correct place to open the package. Consumers are more accustomed to opening the package from one side of the product. The serrated "end seam" has the effect of convenient opening. You can choose to open it from any gap on the left and right, which means you can choose the size of the opening.