Floating Dock is not a new extension for the GNOME desktop. But it was recently updated by its creator to work on the latest GNOME 40 desktop environment, allowing you to have an always visible (or hidden) dock on your screen for launching apps.
As you may be aware, the GNOME 40 desktop environment comes with a major redesign of the Activities Overview that also moves the dock from left side of the screen to the bottom. For me, that makes navigating much easier, but I have to admit that I miss having an always-on dock.