Content or maybe better
For this to work we will need to change the translation key for the menu which means if people used this translation key in the past to hide a menu entry or category, this will no longer work. Renaming the existing entry won't work I presume as the text wouldn't be translated etc.
We will also need to see which guides etc we need to update, and maybe some other wordings in the UI.
👍 for Behaviour, since shows what the users are doing. Might conflict w/ plugins like heatmap/session recording? I suppose it's not a big deal. I think Contents would definitely conflict w/ the Content subcategory.