SVPWM modulation signal

Hello,

I am reading one of your ref design about SVPWM.

I don't understand how a ref signal which is sinusoidal in the 6 sectors space representation can lead to a modulation signal with the same shape than the third harmonic injection ( and I understand it's the way to make the neutral vibrate at 3xf0 to be able to overmodulate and reach Mi=1.154).

But it's not clear how SPWM which create a vref sinusoidal, can modulate the final signal with the shape of the third harmonic injection at the end?

Thanks