You cannot show hovering view of keybindings in Gnome 3.14.
Stephen's answers in comments
* No hovering help menu in Debian, like in Ubuntu (Unity).
* _Keyboard > Shortcuts > Navigation > Hide all normal windows_ where I set the keybinding `super`+`d` to show/hide desktop.
To have Desktop icons in Desktop
* _Tweak tool > Desktop > Icons on Desktop On_
It would be really nice to find a one-liner for this task. TODO