Interesting - do you have a link?

Of course, but I'd rather not share it for obvious reasons. It is a nonsensical biography of a non-existing person.

how do you determine that they know the content of the honeypot?

Presumably the "honeypot" is an obscured link that humans won't click (e.g. tiny white text on a white background in a forgotten corner of the page) but scrapers will. Then you can determine whether a given IP visited the link.

I know what a honeypot is, but the question is how the know the scraped data was actually used to train llms. I wondered whether they discovered or verified that by getting the llm to regurgitate content from the honeypot.

I interpreted it to mean that a hidden page (linked as u describe) is indexed in Bing or that some "facts" written on a hidden page are regurgitated by ChatGPT.

What's the purpose of the honeypot? Poisoning the LLM or identifying useragents/IPs that shouldn't be seeing it?