The Branch is an important object that is part of The Tree; it helps to communicate vital information about space throughout said tree. There are multiple Branches, each of which contain different laws of space, which branch off from the laws of space of the Branch below.
The bottom Branch contains the most "normal" laws of space, such as the fact that containing bodies are bigger than smaller bodies, and the fact that things cannot contain themselves. Due to selfverses that have sizes greater than themselves like The Box existing on our Branch, we are not at the bottom, but rather, near the bottom.
The bubbles within The Branch are impossible to penetrate, but this fact can easily be overriten by changing data in The Core of Everything or if you are given the ability to transcend said bubbles. The ability to transcend the bubbles is natural to the blue version of The Sap for reasons explained in said article.
Because of this, the bubbles in The Branch have wild trans-bubble changes in reality. To prevent collision from these bubbles from being too drastic, blue The Sap exists to randomly swap information throughout The Branch's bubbles.
The material surrounding bubbles of The Sap of The Branch appears to be materials similar to those of The Box; they aren't physical containers, and if you try to "escape" these barriers, then (most) of the time, you will end up back where you started. This allows for insane amounts of energy to be contained within The Branch which have more energy than themselves, giving an beyond infinitely renewable energy source for The Branch.