Lua in cataclysm

I have couple questions about lua files in cataclysm_code.

First
lua/autoexec.lua
class_definition.lua
generate_bindings.lua
Is these file are shared or used related? This is important cause i am working on this https://github.com/CleverRaven/Cataclysm-DDA/pull/6225 and almost finished. I need to know in which dir put this files.

Second
What is main.lua file? user-related or shared?