It seems like they store files (presumably both internal and public) under https://www.nsa.gov/ia/_files/ https://www.nsa.gov/ia/_files/ so I guess it's the way

It seems like they store files (presumably both internal and public) under https://www.nsa.gov/ia/_files/ https://www.nsa.gov/ia/_files/ so I guess it's the way they represent their non-indexable urls.