The menu bar

Yabar's spaces in the menu bar: "code" focused, "web" and "chat" occupied, an empty space 4

Every space is a cell, in the order yabai numbers them:

Looks like Means
A filled box with the name cut out The focused space.
An outlined box The space shown on another display.
Plain text A space with windows.
Faint text An empty space.
A dot at the top right The space holds a stack (or uses yabai's stack layout).
A bar underneath A window on the space wants attention.
A dashed box A native fullscreen app.

A space shows its label when it has one, its number otherwise. With more than one display, the displays are separated by a wider gap, or get an item each (One item per display in Settings).

Click a space to go there. That needs yabai's scripting addition; without it Yabar focuses one of the space's windows, which makes macOS switch to it (an empty space then can't be reached this way).

Right-click (or Control-click) the item:

  • Label Space N…: name the focused space.
  • Scratchpads: when yabai's scripting addition is loaded.
  • Stack Indicators: the style and placement, at a glance.
  • Settings… (⌘,), the version, Check for Updates…, Quit.
  • Last, every space with its windows: pick one to go there. Stacked windows carry their place in the stack.