CKEditor5 does not recognize unsaved changes

CKEditor 4 does not warn when losing changes either in a vanilla Drupal installation.

That's true. I read this and thought to myself "that would be nice, but CKEditor 4 in Drupal doesn't do that on my sites".

Sorry for the confusion. I was mistaken, we use the node_edit_protection → module.

It is a simple but very useful module. I would appreciate it if the CKEditor had this functionality by default. That's why I'm changing the category to feature request.

Thank you very much!