A rolling shutter doesn't cause changes in frequency of the light itself.
The temporal slit appears to be causing frequency changes in the light beam. These frequency changes then interfere with each other creating a diffraction in the spectral frequency (rather than by physical distance as is with the traditional double slit experiment).
The temporal slit appears to be causing frequency changes in the light beam. These frequency changes then interfere with each other creating a diffraction in the spectral frequency (rather than by physical distance as is with the traditional double slit experiment).