Textures:Shaders
What is a shader?
Shaders are short text scripts that define the properties of a surface as it appears and functions in a game world (or compatible editing tool).
By convention, the documents that contain these scripts usually has the same name as the texture set which contains the textures being modified (e.g; base, hell, castle, etc,). Several specific script documents have also been created to handle special cases, like liquids, sky and special effects.
The complete manual is available here