Sharing Options - Confluence Calendar
You can choose between the following sharing options:
Users with existing calendar access
Only users that have permissions to view the calendar in Outlook are allowed to see it.
This requires the users to login with their Office 365 and Confluence account.Everyone with access to this page
All users that can see the page are able to see the calendar.
If the admin enabled anonymous access in the settings, in a public Confluence this might be anyone on the internet.
If you select the Free/Busy Only option, the calendar will be shared with these limited permissions regardless of your permissions.