The inner collar fits into a slight depression in the top edge and two of the outer four are on the outside of the wall and extend about 1/2 inch below the edge. The only actual attachments are the hinges for the lid. One screw for each hinge goes into the back of the freezer, the other into the collar.
Filling the space between the collar walls with latex insulating foam gives it an air-tight seal, top & bottom. If I was doing it over again, I'd put braces between the walls above each shank hole. There's a little too much flex and the taps tend to rotate.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk