The copies don't update themselves, their names aren't files to read again: after a change of the weather or the season the material got its new textures and its copies kept the old ones. They are made again from it then, under their handles. primitive() of an empty handle or one past the banks read out of the bank list; it gives no_primitive there, -1 from the renderer.
Matte_Material() gives a copy of a material with its glossiness damped and its weathering on: the faces cut out of a polished surface, as the sides of a worn rail head, darken and lose the shine by the userdata of their vertices. Tinted_Material() gives a copy whose texture is tinted to a colour as far instead. Both are made once per material.
The weathering and the tint colour have a param slot of their own, param[3]: the shaders of the materials use all four components of param[2] among them (detail, parallax, water, the terrain placement), and light_common.glsl is included in all of them. MAX_PARAMS grows from 3 to 4, the model UBO by 16 bytes. Neither copy is made when another param of the shader lies on the components it would set.