Scratchpads
A scratchpad is an app's window that floats at a fixed place and is shown and hidden with one key, on whatever space you are on. They are yabai's own and need its scripting addition; without it, Yabar leaves them off.
Set them up under Settings → Scratchpads: a name, an app, a title to match (for an app with many windows), and a place
on yabai's grid (rows:cols:x:y:width:height; 6:6:1:1:4:4 is centred, two thirds each way). A new window of that app
becomes the scratchpad as it opens; or pick Make This Window a Scratchpad… in the menu.
yabar scratchpad term
shows or hides it. When the app isn't running, it launches it, and its first window becomes the scratchpad. A running app is never launched again.
Bring Back All Scratchpads in the menu runs yabai's recover, for windows lost after a crash.