It seems like "Scuzz" introduces some side bands. Maybe through something like ring modulation, or additive synthesis. Then there is the delay effect, which will naturally add some additional frequency content when the time isn't a multiple of the sine period.
But with all of those turned down, there are some interesting shapes in the frequency view. Maybe some sort of stereo spread effect that get mixed to mono for the FFT display?
But with all of those turned down, there are some interesting shapes in the frequency view. Maybe some sort of stereo spread effect that get mixed to mono for the FFT display?