In KDE 4 it was possible to configure a Plasmoid Dashboard that essentially worked as an additional layer on your screen where you could put different Plasmoids that you had on your desktop.
It was a very useful feature, it allowed you to have some useful widgets (i.e. sticky notes, weather) at hand without stuffing too much your dekstop.
On Plasma5, I can’t find this anywhere. Am I the one that doesn’t know where to look, or this feature was removed?