It’s called “trusted download.” It requires a line by line review by a person trained in the art of trusted downline, and knowledgeable about the security requirements of the subject matter, sometimes by two individuals. Only plain text. No Office Document can ever be downloaded from a classified system. Retyped as text or printed and redacted, but never downloaded in digital form.
Sounds like you have some knowledge of the process. Do you know what is meant by the term “nonpaper”....as in “turn it into nonpaper”?