For those not familiar, the first variable is the string name of the AddOn, and the second is a private table that is unique to that AddOn. The string is not passed to each Lua file within that AddOn, but the table is passed. This is commonly used to create localization tables in one file, and be able to use it in another. Here's another example.
-- file one
local name, addon = ...
-- prints the same value as ## Title from the ToC.
-- does some stuff
-- file two
local _, addon = ...
addon:SomeFunction() -- defined in file one, but called from file two