Universal Additional Light Data is a component that the Universal Render PipelineA series of operations that take the contents of a Scene, and displays them on a screen. Unity lets you choose from pre-built render pipelines, or write your own. More info
See in Glossary (URP) uses for internal data storage. The Universal Additional Light Data component allows URP to extend and override the functionality of Unity’s standard Light component.
In URP, a GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary that has a Light component must also have a Universal Additional Light Data component. If your Project uses URP, Unity automatically adds the Universal Additional Light Data component when you create a Light GameObject. You cannot remove the Universal Additional Light Data component from a Light GameObject.