The rear ones are hingesI hate those plastic tabs.
The front ones are to keep it on the frame
Dunno why it stands out so much in that pic. They are clear in person
The hinges give access for filtration compartment maintenance without having to remove the lid
If you don’t like the hinges the whole thing can be made as a single piece, or you can not have the filtration area covered. Walter will customize anyway you want and can add or remove anything from the design.
Notches for wires, light mounts, feeders, holes with lids for manual feeding, etc. I dont even think he charges extra for most customizations