Never heard of Arnold AFB, initially thought it was a Guard or Reserve base, till googled it... Arnold Engineering Development Centre ....engine and rocket propulsion test facility that falls under Air Force Material Command
https://www.arnold.af.mil/About-Us/
https://media.defense.gov/2021/Jun/2...ES%20GUIDE.PDF
It is also interesting in the article that AETC was the main subject of his hacks
cheers