what is ical

iCalendar, also known as iCal, is a computer file format for storing calendar information. It allows users to store and exchange calendaring and scheduling information such as events, to-dos, and journal entries. The iCalendar format is supported by many products, including Google Calendar, Apple Calendar, and Microsoft Outlook. It is specified in a proposed Internet standard (RFC 5545) for calendar data exchange and is used for interoperability of digital calendars across different vendors