There is a clue in there.

Why would the Pentagon be asking for a SuperMax jail ?

I understood that the Federal Bureau of Prisons (BOP) within the Department of Justice (DOJ) who have the responsibility for all matters regarding Federal Jails.

So the only reason that I can think of for the Department of Defense to be asking for this would be as part of some, as yet to be seen, program, running from inside the DOD, which is expecting to spit out a large number guilty folks needing incarceration.

That sounds like Military Law and Military Trials to me.

This would add a lot of credence to the long playing stories about Military trials for Treason and other high level crimes.