Saturated Pixels in Contrast Enhacemet

Hi,

I have a basic question regarding the percentage of pixels that are left as “saturated pixels” in the Contrast Enhacement Plugin.
For example, if I set 0.2% of pixels, the plugin will:

a) leave as saturated the 0.1% (0.2% / 2) of pixels at each extreme of the of the histogram–> [0.1% , 99.9 %] ,or

b) leave as saturated 0.2% of pixels at each extreme of the histogram --> [0.2%, 99.8%]

I found contradictory explanations in these two ressources:

Ressource 1
Ressource 2

Thank you
Pedro