Google Calendar Privacy

I’ve been using the premium sleepasandroid for many years but never dared to use the calendar integration option due to privacy concerns.
Today I checked that the permission the app requires is not the event details but general availability. Does this mean the app only has access only to busy/available information, or can the app access specific event information?

Here is the list I’m referring to:

View your availability in your calendars

Make secondary Google calendars, and see, create, change, and delete events on them

See the list of Google calendars you’re subscribed to

See the events on public calendars

See the availability on Google calendars you have access to