I was once reading some documentation (I think for GCP) and there was a weird artifact in the corner of the page, it moved a bit when I moused over it (??) and

I was once reading some documentation (I think for GCP) and there was a weird artifact in the corner of the page, it moved a bit when I moused over it (??) and when I clicked it I got redirected to this site (using the .withgoogle.com TLD). The element never reappeared again. I always wondered why the element appeared on the page. Obviously because "some combination of factors" ultimately returned true - I mean specifically why :)