A notebook at the top of the iCloud folder can't be closed, as the folder would
list it again, so its menu and ⌘K actions offer Delete Notebook, as a local
notebook's do; a server's does not. It asks first, telling of changes not yet
in its files, then closes the notebook and moves its folder to the Trash (the
Recycle Bin on Windows, GIO's trash on Linux), where it can be put back; in
iCloud Drive, on every device. Its replicas and queued edits, display name,
recent places, unread state and fold state are forgotten, and the iCloud
listing can't bring it back meanwhile. Refused, it opens again.

Assisted-by: claude-opus-5.5