UnityEditor.EditorUtility.FindPrefabRoot C# (CSharp) Method

        public static GameObject FindPrefabRoot(GameObject source)
        {
            return PrefabUtility.FindPrefabRoot(source);
        }

 /// <summary>
 /// Determine whether the object is part of a prefab, and if it is the root of the prefab tree
 /// </summary>
 /// <param name="g"></param>
 /// <returns></returns>
 public static bool IsPrefabParent(GameObject g)
 {
     return(PrefabUtility.FindPrefabRoot(g) == g);
 }