How to change the "show desktop" button for a corner bar?

A corner bar is such a strange concept, but afaik existed for a long time. But I cant find how to use it anymore? Is this not available anymore?

Fedora 40, Plasma 6.1.2

Update: found that by default “Super + D” shows the desktop!

And there is a Plasmoid, Show Desktop Win 7 which has a lot of features.

Do you mean this?

Funny workaround!

No, an applet in the panel where you click on.

The exact place where the “show desktop” applet is now, but smaller

It is a strange concept and I can imagine that many people didnt ever use it as it is not described well without an icon. But it is small, and GNOME dash-to-panel has it, Cinnamon has it, Windows has it