What does the script in the braces mean in inspector components?

In the inspector, what does it mean when certain components have “(script)” beside them?

For Example:

Text (Script)
Button (Script)

it means the text and button components are scripts attached to the object.

Unity provides different types of components. Most components are built-in components like Transform, MeshRenderer, SpriteRenderer, BoxCollider, … Those components are specialized component types which have their actual functionality defined in the native code of the engine.

Unity allows you to create your own components inside Mono. Those components are classes derived from MonoBehaviour. Such classes are simply called “scripts” as they define their behaviour as a managed mono class.

The new UI system is mainly written in managed code. Unity even release the UI code under the MIT license over here. All those UI components (Text, Button, …) are compiled into the UnityEngine.UI.dll which is in the extensions folder of the Unity editor. If you want you could even download the source of the UI system, apply some changes to it and recompile it into your own UnityEngine.UI.dll which you can use instead of Unity’s version. However unless you really need to change something (which is only the case when you really understand how it works behind the scene) you usually only use those classes by simply attaching them to gameobjects.