Holidays Rules based on a Variable Date
Variable Date Holidays are based on a given weekday of a given month, such as Labor Day (USA+ Canada) occuring on the first Monday of September.
Election Day (USA)
Days before/after : This option is often used when a holiday rule refers to another holiday. For example in Switzerland "lundi du jeûne" is "the Monday following the Jeûne Fédéral". The Jeûne Fédéral occurs on the 3rd Sunday of September, so the rule for the "lundi du jeûne" would be "1 day after the 3rd Sunday in September".
Another use for this option is when a holiday falls on a given weekday of the month except if the first of the month happens to be that same weekday.
See also: Recurrence Rules Options.