u/Fluffy-Cat4413

Recently purchased this 08 c6, previous owner had passed so I am unable to find info otherwise.

I was looking into getting a mild2wild switch when I discovered this while pulling my onstar fuse. Bottom right fuse location for context, any ideas as to what it is?

I know the car has an immobilizer switch installed but outside of that the car is bone stock so I’m not sure, I just know that the normal npp setup has a fuse there for the whole 3k rpm valve thing.

Thanks!