It doesn't look up or use existing explanations of papers like some kind of internet or database search. You have a fundamental misunderstanding of how it all works.
The fact that you don’t know that GPT was primarily trained on public crawler data and feel inclined to make authoritative comments on it, refuting people who do understand how an LLM works is exactly what I mean by “false sense of knowledge”.
BTW the idea was you paste the article into ChatGPT and ask it to explain the text in laymans terms. Maybe that was the point which you misunderstood. Of course it won't know about papers that it hasn't been trained on.