I was reading the docs about detail maps, and according to this snippet
The detail map can contains albedo (diffuse), normal and roughness (for PBR materials only) channels, dispatched this way (following Unity convention): Red channel: greyscale albedo Green channel: green component of the normal map Blue channel: roughness Alpha channel: red component of the normal map
Unity uses Roughness Texture for the secondary map. I dont see any roughness texture slot anywhere on the Unity Shader… Only Secondary Albedo and Normal… So how could unity be packing roughness into the blue channel of the detail map ???