User blog comment:Dragon-Fox 7/Character Sheet/@comment-24696772-20190329221027/@comment-4867780-20190509223208

John's multiverse is his own creation who the Macroscopic Vault contains replicas of foreign universes created by others or born naturally, that are essentially a tribute to his travels the way people would hang souvenirs in their home.

Though I do have to wonder what purpose these replica would serve, since unlike souvenirs they are evolving existences of their own full of actual people living their own lives, and bound to stray ever further from the original as soon as the slightest non-identical event happens (butterfly effect). If the purpose is simply homage and preservation, a complete sensory-based shareable memory does seem more suitable, like how Brandon Stark can mentally experience any place and time in the Game of Thrones history as if he was there.