How to: 3-element orders enable CENTERED layout:
set -g @powerkit_status_order "session,windows,plugins"  # session LEFT, windows CENTER, plugins RIGHT
set -g @powerkit_status_order "plugins,windows,session"  # plugins LEFT, windows CENTER, session RIGHT
set -g @powerkit_status_order "session,plugins,windows"  # session LEFT, plugins CENTER, windows RIGHT
```

Any element in the middle position will be automatically centered in the status bar.