TYPO3 Core

During a discussion Benni raised the question whether we maybe want to show a note in the backend in the page-view if there is content in some language for which no page-language-overlay currently exists. This can happen when content is copied/cut-pasted from another page (and was already translated) or when an exiting page-language-overlay is removed later.

Please say if UX thinks such a note makes sense, what the message should say (does it point to which language-overlay is missing? ...) and how that message can maybe be dismissed (setting content of the invisible language to deleted? ...).