Search in different sites through the address bar

Just found a chip in chrome, about which I have never read. If you say youtube.com in the address bar, you will notice:



The browser offers to click the tab to search in youtube. After pressing the tab it becomes like this:
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And accordingly, you can enter a search query and press Enter. It works the same with amazon.com, yahoo.com, etc.

Those who knew - sorry, those who are not - not worth thanks! :)