For the moment
Clean Space
Fill the screen with one window while panels close in behind it.
Show me how
Clean Space fills the screen with the active window while two panels close in behind it, on that screen only. Switching to another window ends it.
Turn it on
Keyboard
Press ⌃⌥⇧Z.
Mouse
Click Clean under the quick actions in the menu bar panel.
To turn it on from a Focus automation, see Automation.