The Combat Text Manager controls how the Combat Text System will look. The Combat Text System displays damage numbers when any target is damaged. This works globally for all AI and can even be called for player damage. The Combat Text System is optional and can be disabled through the Combat Text Manager. The Combat Text Manager can be accessed by pressing ctrl+shift+C or by going to Window>Emerald AI>Combat Text Manager in Unity.
Here are the available tutorials and guides for the Combat Text Manager.