Can meshes get baked into save files?

I feel stupid for even asking, 'cause surely no one in their right mind would design a game engine that way, right?

I have a rogue mesh in my game that was part of a long uninstalled mod, and the mesh file is simply not present on my system anymore. There are no loose files and it's not present in any of the remaining .bsa's, yet the mesh is still present in the game.