To get free/busy information from users calendars (https://docs.microsoft.com/en-us/graph/api/calendar-getschedule?view=graph-rest-1.0&tabs=http), the API permissions Calendars.Read or Calendars.Read...
Getting just the availability view information (and not the calendar events as well) is exactly what I would like too. In addition to the privacy issues, the network load is unnecessary for my purposes, as I don't need the entire calendar detail. sebastianheil I should have read your original post more carefully. I agree that a more restricted permission--in addition to the option to just get the availabilityView--would be a great addition.