User blog comment:B214/Question and Answers 6/@comment-71.221.19.123-20180330160805/@comment-34652373-20180331173537

That's explained on Volume 23. Quoting Ajuka:

"I will be establishing a secret intelligence bureau. Using an example from the human world, it would be similar to the American CIA, or the English MI6". "We plan to name the organisation [EXE]".