Theories by user Rusty Kerman.
Tesseract/Xen Theory (unvoted)Edit
To Start off this is my first theory so sorry for lack of punctuation, run on sentences, tangents, EXT.
I will be focusing on the Structure of the submachine NOT lore, teleportation, EXT.
I see the Submachine or Subnet as a large amount of "bubbles of universe. I will call them Sub Zones"
Each Sub Zone contains a small portion of the universe but in 8 levels of reality and ALL of time for the location. Like in the Tesseract in the movie Interstellar. One location in space stretched thought all of time.
Now "Sub Zones" are able to merge : EX The Pyramid and the Temple in Sub 9.
It can be destabilized by holes in the "bubble" being Karma Portals Destroying reality around it.
Now to the XEN part of the theory. I Believe the Submachine is a place BETWEEN realities.
For a way to visualize it: Imagine a room with bumps evenly spaced around the floor. Then fill the room with water. The bumps would be universes while the water would be the Submachine.
To Finish off: Thanks for reading and Good luck on your Adventures in the Subnet.