Can they not tweak specific word variations to track down where the leak is coming from? You can narrow it down to which department the leak is coming from at least.
Is there a name for that? Steganography? Watermarking? Both don’t specifically describe the idea of swapping words or homographs (rn = m) to embed the name of the person who received a copy of a document to bust the leaker.
Honestly, that requires a pretty gullible leaker. If the person leaking information cross-checks what information coworkers got and doesn't leak identifiable documents (others mentioned unique watermarks) it's probably going to be hard to track them down
