Good Q! There are two cabinet styles - face frame and frameless. These are frameless style because they are just the cabinet case - the sides, bottom/top, and back. This is a European style, and a lot of modern cabinets utilize this construction method.

Face frame cabinets are built with the case - sides,b/t, and back - and then a frame is placed on the front of the case. This is a traditional American style, although in general most of what we are building in today’s world are frameless cabinets. https://i.nostr.build/W20R.webp