It should be possible. nroff macro language has looping, string interpolation, functions and if/then/else. That macro language should be turing complete. People have written file-infecting virus malware with it, I believe, which indicate that a quine should be possible. I personally have made several attempts at an nroff quine over the years with no success.
If it's not possible, I'd love to see an explanation, so that task can quite weighing on me.
If it's not possible, I'd love to see an explanation, so that task can quite weighing on me.