This inlay replaces the original inlay for the game and can be now used with sleeved cards. The dimensions are chosen in this way so that you can store the board on top if you want to use it.
If you chose to replace the board with the really nice deck divider from Leron (https://www.printables.com/@Leron_223334) https://www.printables.com/model/421259-fugitive-2nd-edition-deck-divider you can store the the board underneath.
The author marked this model as their own original creation.