All delete operations are permanent, with no Undo mechanism.
Deleting entries or lists in the Second / Cloud folder will be propagated to iCloud and all devices that are synchronised with iCloud. To enable this, ListHolder keeps only a numeric tag of the deleted item (until synchronisation); the data itself is permanently deleted and not recoverable.
When not in editing mode, entries can be quick deleted via a leftward swipe across the entry. This is true for both the list of titles master pane, and the list entries in the detail pane.