In Kate version 23.08.5, the option to automatically close the Kate window when the last file/tab is closed no longer exists. Previously, this behavior was available as “Close Kate entirely when the last file is closed”, which allowed users to have Kate exit completely when no documents were open. Many users, including myself, expect the editor to close when the last file is closed. The current behavior, which always opens a new blank document, can be disruptive to workflow and differs from past versions. Requested Feature: Please restore the option to close Kate entirely when the last file is closed, ideally with a user-selectable setting in Settings → Configure Kate → Behavior, so that users can choose between opening a blank document or closing the editor completely. Thank you for considering this request.
The setting is here in version 25.08: Settings → Configure Kate → Session → Application Startup/Shutdown Behavior → Close Kate entirely when the last file is closed Don't remember when it has moved