That's a good question, one I thought of, but have put off grappling with.
Based on what LLMs have given me for answers so far, I'd look harder for the human-written source of the nroff code. I have written what I believe to be the only quine in the GPP macro processing language, LLMs only refer me to my code if I ask for a GPP quine. Google, Meta, OpenAI really have strip mined the entire web.
If I genuinely thought anything creative or new appeared, I'd probably be at a loss as well.
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.
Based on what LLMs have given me for answers so far, I'd look harder for the human-written source of the nroff code. I have written what I believe to be the only quine in the GPP macro processing language, LLMs only refer me to my code if I ask for a GPP quine. Google, Meta, OpenAI really have strip mined the entire web.
If I genuinely thought anything creative or new appeared, I'd probably be at a loss as well.