Coverage and status

Every date carries two labels.

Coverage says where the date comes from:

coverage	Meaning
verified	The year was checked against an official source, which the calendar cites.
library	The date comes from the open-source holidays library and hasn’t been checked against an official source yet.

A calendar’s verified_years lists the years checked, and last_verified_at says when. Answers that combine dates (T+N, counts) report the weakest coverage involved, and estimated: true when any date involved isn’t confirmed.

Status says how settled the date is:

status	Meaning
confirmed	Announced by the authority.
estimated	Calculated rather than announced, such as a holiday that depends on the moon.
provisional	Expected but not yet announced, such as a date set each year by proclamation.

On this site, verified dates show a green verified tag, and provisional ones a provisional tag.

Islamic holidays

Eid al-Fitr, Eid al-Adha and the other Islamic holidays follow the lunar Hijri calendar, and most countries confirm them only days ahead, after the moon is sighted. Until then every day of the holiday is estimated. When the government, central bank or exchange announces the dates, they become confirmed and cite the announcement; if the dates moved, the change feed shows the old and the new days. To be told as it happens, add a webhook or email alert: the holiday.confirmed event fires when an estimated holiday is confirmed.

All the days of one holiday share one status, so a five-day Eid is never half confirmed.