They will come in handy.

After the repair, the remains of extra wallpaper always remain. They will come in handy. From them you need to cut a small piece equal to the size of the spot. It should be borne in mind that the drawing and texture on a piece and on the wallpaper themselves exactly match. Now it needs to be attached to the wall and carefully cut out the flap of wallpaper with contamination. It is necessary to ensure that the template piece does not move, otherwise you will have to cut out another.