A seventh main track is present in the debug menu, but since there's no track that is set to it, the debug menu will restore the option set by the game.

It's unknown what track that would have been on it's value. Seeing as Stunt O Rama is like the six main tracks, it would have been set to that value, but Stunt O Rama is untextured and there are a lot of other stuff that were not fixed. Also, the AI cannot drive on it because there's no AI path and no timer on it.