X3D version 4.0 was approved by Web3D Consortium and ISO in 2023.
X3D version 4.0 offers many new features including interoperability with HTML5, glTF
2.0 Physically Based Rendering (PBR), and Web Audio API.
<Script DEF='Clouds'/> contained CDATA source block needs initialize() method when no fields and no url
are defined, otherwise has no action