Model: Data URL

A model source can use a data URL to embed a model file inline, without a separate network request.

<model alt="A model of a cube">
  <source src="data:model/vnd.usdz+zip;base64,UEsDBAoAAA..." type="model/vnd.usdz+zip" />
  <source src="data:model/gltf-binary;base64,Z2xURgIAAA..." type="model/gltf-binary" />
</model>