Main/Meta/Music/Sandbox

Alright, so you're playing a game or watching a movie that has a Medieval European Fantasy style setting with a little bit of City Noir on the side. Interestingly, all the music, be it the Theme Tune or action music, is done in a techno-industrial style while the only music that exists in universe is typical high-brow orchestrated stuff. You've just stumbled upon the concept of Meta Music. This is when the music presented to the audience is in a certain style, usually one that matches the mood and thematic elements of the work, while that same style doesn't exist in the world that the work is about. A clearer example would be if a period piece about mobsters suddenly used modern electronic music for its action bits because it helps reinforce the adrenaline of the scene. If its used to reinforce the mood of a work of fiction, without actually being in it, its Meta Music.

Compare Thematic Theme Tune, where the lyrics of a song don't speak direcly about the work, but capture the mood and idea of it.