[Halja]

Variable scope is always a fun question. I may have this wrong but here I go.

Game Global (G_) is a lua table and global to all

Ad-on's SavedVariable is lua table inside G_ and is global to all your add-on files.

lua file

var1 = "something" --is available to all files in the add-on
local var2 = "something" -- is scoped to the file only
local function

local var1 = "something" -- is scoped to the function call only

lua Class

local var1 = "something" -- is scoped to every thing in the class
local function

local var1 = "something" -- is scoped to the function call only

The 'include' part is the <ad-on>.txt file. I have not played with Bindings type files. So, I can not speak to the scope of those.
--halja