Surplus part came with my dishwasher
The manuals can be downloaded by entering your product number at this link.

This part attaches to the bottom-front of the dishwasher when you install it as a built-in (see page 2, step 1-6). You remove the excess from this part by cutting it along one of the groves (see page 2, step 5). This then becomes a toe kick that should somewhat resemble the location of the toe kick along the rest of the built-in cabinets in the kitchen.