My theory for the H2A terminals**SPOILERS**

To my knowledge, no videos of the H2A terminals have come out. They will likely tell the backstory of installation 05 just like the terminals in CEA told the backstory of installation 04. My theory is that Spirit of Fire(the ship lost in space from Halo Wars) will crash land on installation 05. We know that at some point in the past, a large number of sentient beings had to have been on installation 05 in order for the flood to prosper to the point of producing a gravemind. Spirit of Fire crash landing(or maybe even a deliberate landing upon discovering the halo ring) would certainly give the flood all the food they need. That is, provided the crew of Spirit of Fire release the flood from containment through some means. A ship of that size would give the flood all the food it needs to eventually form into a gravemind like the one presented in H2A. It would also serve as a convenient way for the writers to write Spirit of Fire out of the story without needing to do so in game and explain to players who skipped Halo Wars who they are and why they’re already experienced with the flood. Perhaps some flood infection forms could have stowed away on Spirit of Fire when it escaped from the shield world in Halo Wars.

Gravemind did say, “I am a monument to all your sins”. Perhaps this could be referencing its recent experiences with humanity when Spirit of Fire showed up. They did terrible things, died, and now gravemind is literally a living monument to their deaths and consumption.

The terminals are the back story of the arbiter which has already been confirmed. Also they have certain things that link to halo 5.

Oh ya, that’s right. I do remember hearing about that. Well, nevermind then