While the Mac Mini is not an SBC, as it runs a full version of macOS, some see it as a single-board computer because it only has one connection to the outside world, in a way that many SBCs do.
The Mac Mini is small, lightweight, and has a powerful processor, all ideal features for a portable computer, so one maker has used one to create a portable all-in-one (AIO) computer.
The problem lay in how to make it portable without the need for a separate keyboard, screen, and the Mini, so the maker attached the Mac Mini to the side of a keyboard, creating a compact unit.
The solution was not perfect, however, so the maker altered the design, attaching the screen to the main unit using rests to hold it in place when closed, creating a more polished product.
This is not the first time this maker has used a Mac Mini to create a portable system, previously using it to create a ‘luggable’ version of a portable computer.