See the original idea by stduerre 
https://planet4.greenpeace.org/idea/add-an-internal-title-to-pages/

Editors sometimes set up multiple landing pages with similar content for different audiences.

It would be useful for them to be able to set an internal title for pages (that’s not visible to the public) to keep an overview of the different pages. The internal title would appear in the pages list in WP Admin and in a separate field in the editor, but not in the front end.