As we were tooling down the highway on a test ride, the cover fell off this area- see photo.
I went online to Jayco’s parts catalog but could not find this cover that is 26x26.
Lost mine last year and ordered a new one from a small RV repair shop. You'll need the exact size when ordering because there are 100s of sizes. You can't buy just the cover you have to buy the frame also. I now have two pieces of white tape holding that cover on. Take a picture of it when your at the dealer because some have the tabs on the bottom and yours are on the top.
I have never looked for one. But if there really is 100's of different models of these out there, I would call Jayco with your vin number, and ask if they can look up on the build sheet for the part number.
I am not sure of the exact name, but it is referred as Refrigerator Access Vent
From the photo it looks like you've lost the cover to your outside refrigerator access panel. This should be a fairly common size and should be available at most RV parts stores. Just tell them the type/size of frig and they should be able to order for you if they don't have one in stock.