That’s because the Hilbert.ny does not have a menu. I don’t know what that “manual” (your link) is referring to, but the Hilbert.ny plug-in does not do what the text says.
My guess - The text is AI generated nonsense.
What the Hilbert.ny actually does:
It shifts the phase of each frequency component of a signal by 90°. Assuming that clipping does not occur, there will be no audible change to what it sounds like.
The original Hilbert.ny page: Hilbert transformer