The holiday object

The API will of course return Holidays.
The holiday object consists of:

id: the ID of the holiday (do not rely on this ID, as it can and will change. It may be removed in a future version
date – ISO Date String of (start)-date in local format
start – start time & date of holiday
end – end time & date of holiday
name – name of holiday in English. Local & other languages are not yet supported.
type – type of holiday (one of: public, bank, school, optional, observance)
substitute – indicates if holiday is a substitutes for another holiday (for example, a bank holiday falls on a weekend, then Friday or Monday will be the substitute)
note – (optional) note. Usually empty, but may include a note

Dates

start and end are the start/end date of the holiday within the selected timezone of the country, state, region.

Name

The name in English. Local or specific language are not supported, yet.

Types of holidays

Currently the following types are supported

public: public holiday
bank: bank holiday, banks and offices are closed
school: school holiday, schools are closed
optional: majority of people take a day off
observance: optional festivity, no paid day off
Additionally a note field is sometimes available for further clarification.