Where can I find them to copy? I’m intrigued.
Just use any SDK, like the one from fiatjaf. Or any command line interface with search or query function. Or an API, like Nostr.Band or Nostr.Wine has. The machine just queries at regular intervals for certain sorts of data. If they include machine learning, the query gets refined over time.
Have you thought of making a class or tutorial? @Uno is making an About Nostr resource and if coding for Nostr is simple, I could imagine a section on that would be a very cool idea.