Learning the highest levels of Lua Programming, where?

Greetings!

I have been scripting for roughly 6-7 years now and have been looking around at learning the extremely advanced parts of Lua particularly environment/stack manipulation and things of that sort. Things that you would never see in games outside of, for example, Script Builder's.

I quit scripting on and off fairly often so I tend to miss new Lua based things. For example, I missed the entire era of HttpService, I missed the entire era of ModuleScripts, FilteringEnabled, etc.

Therefore, it would be great if someone could give me some insight on learning the higher levels of Lua programming. This may seem silly as environments are never used when creating games. However, it still would be nice to learn them as Roblox isn't the only place Lua exists.

Anyway, thanks for the assistance.