There's a really, really simple solution to all of this: anytime any factor outside of the main game is used to modify the game itself, it's usually considered a mod. There's a whole conversation about the difference between modifying code, modifying game assets and whether or not third-party rendering and shader utilities like ENB classify as a mod. It's kind of funny because in the Kotaku comment section, there's a big argument over a line in the article about this particular discovery not being a Fallout 4 mod, even though it clearly modifies the game's visual look.
