Do you know which is the most popular GNOME extension out there?

I don't know for sure, but if I have to make a guess, I would say Dash to Dock is a good candidate for that title.

Why do I say that? Because at the time of writing this article, this extension has more than ten million downloads.

What is Dash to Dock?

In the clean GNOME layout, you don't see any quick launcher. It's just the wallpaper. You press the Super key (Windows key), a launcher appears at the side or on the bottom. This launcher is called Dash in GNOME. The Dash to Dock extension takes the "dash" from GNOME Activities Overview and "docks" it to make it visible on the desktop all the time.