Added to the mash runnings before the boil starts.
In the boil for HopAddition.timeMinutes minutes.
Whirlpool / hop stand after flameout.
In the fermenter. Contributes 0 IBU.
In the keg. Contributes 0 IBU, like a dry hop. It has no time, because the beer sits on it until the keg is empty and there's no contact time to measure.
Where in the process a hop is added.