The Infinite
“The Infinite” was a “bridge-reality” or “bridge-universe”, (PROSE: The Disappearance of Jenny Everywhere) a “place between realities” which served as “sort of a home” for Jenny Everywhere (COMIC: The Mind of Jenny Everywhere) with an endless starry night sky and a simple, smooth, black floor. (COMIC: The Jenny Everywhere Chronicles, etc.) Each star represented a universe. (COMIC: The Mind of Jenny Everywhere)
It had a connection to Jenny Everywhere's shifting powers; one way for her to shift was to pass through the Infinite, (COMIC: The Beginner's Guide to Multiversal Theory, The Jenny Everywhere Chronicles) which she would usually find filled with a crowd of her other selves. Most were only passing through, but some resided there permanently, performing “various tasks”; (COMIC: The Jenny Everywhere Chronicles) indeed, there existed an entire “culture” of Jennies within the Infinite. (COMIC: The Mind of Jenny Everywhere) Jenny could also mentally tap into the Infinite to view potential events, without physically going there. (COMIC: Governing Council)
Only Jenny Everywhere could travel to the Infinite; it was normally impossible for other shifters to enter it. However, while desperately looking for Jenny after she disappeared from all of reality without explanation, Jenny Anywhere and Hakhe combined their skill at modulating shifting with Laura Drake's bond with Jenny and Jenny Somewhere's genetic kinship with Jenny, and managed to force a shift into the Infinite. Michael Wherever and the Illumination also managed to fly the Wilson into the Infinite by “connect[ing him]self, a cache of Jenny’s genetic makeup, and a ludicrous amount of power to the ship’s computers”. (PROSE: The Disappearance of Jenny Everywhere)
A version of Jenny was once seen shifting through the Infinite as an example used by Doctor Sigma during a talk on common methods of Multiversal travel. (COMIC: The Beginner's Guide to Multiversal Theory)
Behind the scenes
As he noted in a convention panel, Benj Christensen did not initially mean for the Infinite to be an open-source concept. However, he was surprised but happy to see other people start to use it, seemingly under the assumption that it was part of the Jenny Everywhere “package”, and eventually released it into the public domain to join Jenny herself.