Roughness is only included in the API as a default value if, say, a plugin, would access the data and create a material in an application. Then it would get an approximate roughness value, so glass is glossy, and…
Like subb said, "sRGB Linear" means sRGB primaries without the sRGB EOTF (gamma curve) applied, which you could say is "raw linear" values, the most common way to input colors in 3d applications.
Roughness is only included in the API as a default value if, say, a plugin, would access the data and create a material in an application. Then it would get an approximate roughness value, so glass is glossy, and…
Like subb said, "sRGB Linear" means sRGB primaries without the sRGB EOTF (gamma curve) applied, which you could say is "raw linear" values, the most common way to input colors in 3d applications.