The page states:

In late 2023, a Reddit user known as "evilscientist311" conducted a comprehensive analysis of Cleo's activity patterns and interactions with other Stack Exchange accounts.

However, I and others were on the scent at least as far back as April, 2023. See for example: https://x.com/TheDavidSJ/status/1650957407902658571

Edit the wiki and add it!