A:Answer Hello, thank you for your question. The part that you are referring to is the rear trim piece. The rear trim piece is necessary for your range to properly function as it ensures proper airflow around the unit. While we do not anticipate that you will have any issues with your range, should something occur and the cause were to be from installation issues concerning the rear trim piece, you would not be covered under your range's one-year limited manufacturing warranty. If you would like to read more about this warranty, you can do so on page 26 of the owner's manual, found on the product page on our website. We hope this helps! -Chris@GEA