In 2014 we ordered a whole bunch of stuff from Japan. Randomly these were also sent to us. When we contacted the seller they told us that it was their mistake and we could keep them. Not really knowing what to do with them we put them into storage until now!
These are reproduction boxes for the original Japanese GameBoy. As you can see on the back of the box they are not original and are designed for people who want to put in custom GameBoy consoles, just want a box to display, or have a box for their loose console to put into their collection.
They are very well made. Some of the internal tabs have bends and creases, but the display areas of the box on the outside are all in nice shape.