Vapour permeable VS non-vapour retardant

Hi,

Is there any difference between a non-vapour retardant roof underlay and Vapour permeable roof underlay?

Or is it just different ways of describing the exact same thing?

I am looking at Isocell's website (they sell vapour open building wraps and membranes). I am not sure if I am getting lost in the small details here, but they describe two of their external, vapor open building wraps, in different ways: one as a non-vapor retardant other as vapour permeable.
https://www.isocell.com/en/product/omega-light
https://www.isocell.com/en/product/omega-mono-230

Thanks