According to the documentation (here), Google provides somewhat identical scopes:
https://www.googleapis.com/auth/calendar read/write access to Calendars
https://www.googleapis.com/auth/calendar.readonly read-only access to Calendars
https://www.googleapis.com/auth/calendar.events read/write access to Events
https://www.googleapis.com/auth/calendar.events.readonly read-only access to Events
What is the difference calendar.readonly and calendar.events.readonly? And what's the difference between the non readonly ones?