The Void is the 'space' between universes in the Multiverse.

The Void is an extremely dangerous 'place', because of its unique behavior in regards to time and space.

It is not connected to Temporalis, because it has no known timekeeping protocol. It exists in a state where all universes (past, present, and future) exist simultaneously. This means that any travel to there likely results in being stuck in a sort of endless state of time-stasis. No person or device that's travelled there has made it back, resulting in no way to confirm what form matter takes outside of universes.

Temporalis is a small hub universe / city that tracks the flow of time in most areas of the Multiverse.

The fact that bubbles of 'stuff' (i.e. universes) can exist with their own timekeeping protocols inside the Void suggests that its fundamental operation is either at a higher dimension than the third, or that the void acts as an abstract container for universes, not actually existing within any known format of physical space. Either case means that very little infromation can be extracted in regards to how universes are constructed.

Interuniversal travel avoids this problem altogether, by using the only information left by the AI before their disappearance: warp travel.

Warp Travel is the technology the AI leave their creator-species before their departure.