Demo Ruins not work

Hi,

The ruins demo on the site no longer works

https://www.babylonjs.com/demos/ruins/

Error in the console :

Uncaught ReferenceError: __extends is not defined
    at babylon.SkyMaterial.js:14
    at babylon.SkyMaterial.js:25
    at babylon.SkyMaterial.js:241
babylon.js:1 Babylon.js v4.0.0-alpha.10 - WebGL2
babylon.js:1 BJS - [16:50:59]: Unable to load from /Scenes/Ruins/ruins.babylon: loadAssets of unknown
	Lights:
		Name: Spot001, type: Spot, animation[0]: Name: position, property: position, datatype: Vector3, nKeys: 7, nRanges: 0, animation[0]: Name: isEnabled, property: _isEnabled, datatype: Float, nKeys: 6, nRanges: 0, animation[0]: Name: diffuse, property: diffuse, datatype: Color3, nKeys: 10, nRanges: 0, animation[0]: Name: specular, property: specular, datatype: Color3, nKeys: 10, nRanges: 0, animation[0]: Name: intensity, property: intensity, datatype: Float, nKeys: 7, nRanges: 0
		Name: PointLight, type: Point, animation[0]: Name: isEnabled, property: _isEnabled, datatype: Float, nKeys: 6, nRanges: 0, animation[0]: Name: intensity, property: intensity, datatype: Float, nKeys: 6, nRanges: 0
		Name: thunderstorm, type: Point, animation[0]: Name: intensity, property: intensity, datatype: Float, nKeys: 12, nRanges: 0
	Animations:
		Name: ambientColor, property: ambientColor, datatype: Color3, nKeys: 6, nRanges: 0
	Materials:
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
		Name: undefined
g._ErrorEnabled @ babylon.js:1
babylon.js:1 BJS - [16:50:59]: Unable to load from /Scenes/Ruins/ruins.babylon: Error in onSuccess callback