Unloads all objects which were loaded from the scene's serialized file. Without this flag, only GameObject and Components within the scene's hierarchy will be unloaded.
Note: Objects that are dynamically created during the build process can be embedded in the scene's serialized file. This can occur is when asset types are created and referenced inside the scene's post-processor callback. Some examples of these types are textures, meshes, and scriptable objects. Assets from your assets folder will not be embedded in the scene's serialized file.
Note: This flag will not unload assets which can be referenced by other scenes.