Unlinked domains can definitely be found in a lot of ways, but like I show in the article there was literally no fetching of the page except for Googlebot. So even if the hostname was leaked somehow the contents of the page require fetching the page, which was only done by Google. Also like I show in the article the content that ChatGPT knows identically matches what's in a Google search snippet, down to where a word-break is.
Oh, yes you’re right. I didn’t read the whole thing, which was clearly a mistake. I apologize. Good job with the article, and thank you. It’s pretty funny that they only get the excerpts.