I've notified our documentation team about the broken link. I believe the link is meant to direct you to this page. I believe this setting is mean for the legacy s_vi cookie used with Analytics. Since you've deployed the Marketing Cloud ID Service (MCID), this setting wouldn't be of much use (unless you have grace period turned on still).
The AMCV cookie used in the MCID has an expiration of 2 years. You can view it's documentation here.