X3D version 4.0 was approved by Web3D Consortium and ISO in 2023.[/X3D, diagnostic]
X3D version 4.0 offers many new features including interoperability with HTML5, glTF
2.0 Physically Based Rendering (PBR), and Web Audio API.[/X3D, diagnostic]
<meta name='TODO' content='add viewpoints'/> [/X3D/head/meta[8], diagnostic]
<meta name='TODO' content='DEF/USE for all duplicated nodes to ensure consistency'/>
[/X3D/head/meta[9], diagnostic]