This is a spacer for the 270 degree hinge below. I felt the gap between the door and printer was too large so I made a small space.
Original here: https://www.printables.com/model/544884-creality-k1-max-270deg-door-hinges-w-door-latch/remixes
The author remixed this model.
Created a spacer to reduce the gap between the door & printer.