Lightmodel
==========
A _lightmodel_ is a set of parameters describing environment lighting conditions, atmospheric scattering, fog, etc. A Lightmodel Mod Item allows you to bundle together several lightmodels with predefined name structure, corresponding to several times of day; the game then smoothly interpolates between them depending on the current time.
You need to provide a way to make the game switch to the lightmodel set provided by you, e.g. by adding a Code mod item in your mod.