The Specific Holidays Sets Modifier is appended to most of the available holidays tokens in the following form :
where XX is the position of the set in one of the aeiou-Holidays Lists.
If you want to also include duration modifiers, then these should be added after the specific holidays set modifier. For example :
Specific holidays set modifiers are often used to list holidays of many holidays sets over a year in holidays page.
See also: GetHolSetNameOfId.