Limbo's little carved cavern, once probably intended to be a burial of some kind, he finished hollowing out some sections and now uses it to keep his own items of interest. A pile of trainer's jackets and blankets and sleeping bags left behind now keep piled in the biggest of the nooks for his naps. The other several cubbies lining the walls of the small room are stuffed with misc. items he's found on his patrols. Stoned, dropped equipment, dexes, some really unfortunate mons lost/trapped in balls. And so on.