The new format property on the Material is not documented

[benpigchu]

Is your feature request related to a problem? Please describe.

I'm trying to make a transparent version of a opaque object imported from GLTFLoader. However, the old way to do it (set transparent to true on the Material) do not works any more. After some investigation I found that #22428 changed how the renderer decides whether a Material is opaque in r132, so I changed my code to both set transparent to true and set format to RGBAFormat, and it works.

However, the format property on the Material is undocumented and it is confusing to see the code breaks in the new version.

Describe the solution you'd like

Add documentation about the format property on the Material, and also document how it affects rendering

Describe alternatives you've considered

Just revert the change, but I think it is not practice.

Additional context

Previous discussion on making a GLTF imported model transparent on the forum