Sorry for the confusion. Multi-monitor support is only briefly mentioned in the docs[1] and the interactive tutorial[2].
Jwno's internal data structure has these levels (higher-level comes first):
Root - Virtual Desktops - Monitors - Normal Frames - Windows
So monitors are part of a virtual desktop, and every virtual desktop has the same layout that reflects your physical monitor arrangement. When you switch virtual desktops, all monitors switch to the new desktop at the same time.
[1]:https://agent-kilo.github.io/jwno/frame-tree/frame-nodes.htm...
[2]: https://github.com/agent-kilo/jwno/blob/master/example/tutor...