Highlighting visited links in Google search results

Today I noticed that Google in search results highlighted some of the links as visited. It is interesting that for the first time I used this search query at home on the weekends and, in theory, the browser on the working computer should not know what I had visited at home there. I asked a question on Habré and they write to me that, they say, the backlight is a function of the browser and my synchronization is set up. No, I do not have any synchronization.

To check - who is still to blame, I launched the donkey and logged in to Google. I use the donkey extremely rarely, it is also difficult to suspect him in sync with FF, so the experiment should be fairly clean. As a result, the same links were highlighted in the issuance and in the donkey. Yandex in both browsers says that the links are not well-known. If you logged out in Google, then the links become unmarked again.

Behind this all, except that I apologize in advance, if this behavior has long been known, studied and does not cause surprise to the progressive public - I, frankly, only paid attention today.