If you need to see a list of the URLs for a user’s calendar that has been published for Internet access, you can use the following cmdlet:
Get-MailboxCalendarFolder “user”:\Calendar | Format-List
This cmdlet displays information for the specified calendar folder, including the calendar folder name, whether the folder is currently published or shared, the start and end range of calendar days published, the level of details published for the calendar, whether the published URL of the calendar can be searched on the Web and the published URL for the calendar.
