A leg to stand on?

Trying to figure this one out? Seems the bottom bunk had a slide in and out extension to the bed? Slide it in for a nice sitting couch and more floor space, slide it out for a bigger (41" wide) bed. The sliding seemed to be just plywood on plywood and prone to jamming. Doesn't seem like something a professional camper company would build, but I can't find signs of "user customizing" in this area. That door you see under the slide out accesses the same under-bed storage as the outside hatch to the right of the main door.