Well Chrome does have an installation identifier that was/is transmitted only to google properties. That would explain the behavior you describe. Google says i

Well Chrome does have an installation identifier that was/is transmitted only to google properties. That would explain the behavior you describe. Google says it is only for tracking experiments and tests, but I doubt even they know what everybody is doing with it, and perhaps you were a member of an experiment where they used it to track you. "Google tracks individual users per Chrome installation ID" [0] An article about it was here [1] Discussion on hackernews was here [2] [0] https://github.com/w3ctag/design-reviews/issues/467#issuecomment-581944600 https://github.com/w3ctag/design-reviews/issues/467#issuecom... [1] https://www.theregister.com/2020/02/05/google_chrome_id_numbers/ https://www.theregister.com/2020/02/05/google_chrome_id_numb... [2] https://news.ycombinator.com/item?id=22239641 https://news.ycombinator.com/item?id=22239641