Excerpt from https://twitter.com/pixelpartner/status/1592504644382887936

SuzanneWith2UVMaps_iOS16.usda

def "_materials"
{
    def Material "Suzanne"
    {
        token outputs:surface.connect = </_materials/Suzanne/preview/Principled_BSDF.outputs:surface>

        def Scope "preview"
        {
            def Shader "Principled_BSDF"
            {
                uniform token info:id = "UsdPreviewSurface"
                float inputs:clearcoat = 0
                float inputs:clearcoatRoughness = 0.03
                float3 inputs:diffuseColor = (0.5438262, 0.8000001, 0.04044797)
                float inputs:ior = 1.45
                float inputs:metallic = 0
                float inputs:occlusion.connect = </_materials/Suzanne/preview/AO_Texture.outputs:r>
                float inputs:opacity = 1
                float inputs:roughness = 0.2564767
                float inputs:specular = 0.023316056
                token outputs:surface
            }

            def Shader "AO_Texture"
            {
                uniform token info:id = "UsdUVTexture"
                float4 inputs:bias = (0, 0, 0, 0)
                asset inputs:file = @./textures/aoc.png@
                float4 inputs:scale = (1, 1, 1, 1)
                token inputs:sourceColorSpace = "sRGB"
                float2 inputs:st.connect = </_materials/Suzanne/preview/AO_Map.outputs:result>
                float3 outputs:r
            }

            def Shader "AO_Map"
            {
                uniform token info:id = "UsdPrimvarReader_float2"
                token inputs:varname = "st"
                float2 outputs:result
            }
        }
    }

    def Material "Torus"
    {
        token outputs:surface.connect = </_materials/Torus/preview/Principled_BSDF.outputs:surface>

        def Scope "preview"
        {
            def Shader "Principled_BSDF"
            {
                uniform token info:id = "UsdPreviewSurface"
                float inputs:clearcoat = 0
                float inputs:clearcoatRoughness = 0.03
                float3 inputs:diffuseColor.connect = </_materials/Torus/preview/Image_Texture.outputs:rgb>
                float inputs:ior = 1.45
                float inputs:metallic = 0
                float inputs:occlusion.connect = </_materials/Torus/preview/AO_Texture.outputs:r>
                float inputs:opacity = 1
                float inputs:roughness = 0.5
                float inputs:specular = 0.5
                token outputs:surface
            }

            def Shader "Image_Texture"
            {
                uniform token info:id = "UsdUVTexture"
                asset inputs:file = @./textures/color.png@
                token inputs:sourceColorSpace = "sRGB"
                float2 inputs:st.connect = </_materials/Torus/preview/UV_Map.outputs:result>
                float3 outputs:rgb
            }

            def Shader "UV_Map"
            {
                uniform token info:id = "UsdPrimvarReader_float2"
                token inputs:varname = "map"
                float2 outputs:result
            }

            def Shader "AO_Texture"
            {
                uniform token info:id = "UsdUVTexture"
                float4 inputs:bias = (0, 0, 0, 0)
                asset inputs:file = @./textures/aoc.png@
                float4 inputs:scale = (1, 1, 1, 1)
                float2 inputs:st.connect = </_materials/Torus/preview/AO_Map.outputs:result>
                float3 outputs:r
            }

            def Shader "AO_Map"
            {
                uniform token info:id = "UsdPrimvarReader_float2"
                token inputs:varname = "st"
                float2 outputs:result
            }
        }
    }
}