These are the permissions requested by the app during the install process. Here you also can find a short description why I need a specific permission.
android.permission.READ_CALENDAR and android.permission.WRITE_CALENDAR
The app is designed to interact with the calendar so it needs the right to read/write the calender e.g. to store new appointments.
android.permission.INTERNET and android.permission.ACCESS_NETWORK_STATE
The app can sync with various internet and network sources. So it needs the right to access the network.
android.permission.READ_PHONE_STATE
For licensing the app needs access to device id.
android.permission.WRITE_EXTERNAL_STORAGE
The app can import/export calendar information based on files stored on the device so it needs the right to access the devices storage.
android.permission.RECEIVE_BOOT_COMPLETED and android.permission.WAKE_LOCK
This permissions are used for the autosync service. If the device reboots the autosync service will start automatically. To prevent interuption of the autosync process the app must be able to prevent the sleep mode temporarily. At the preferences it is also possible to allow the app to working during standby on manual triggered sync.
android.permission.ACCESS_COARSE_LOCATION
To detect which WIFI networks are in range to the device, i.e., to configure the app so that it syncs only when it is connected to a specific network.
android.permission.ACCESS_WIFI_STATE
This permission is used for the autosync service to prevent the app from syncing if no WIFI/WLAN connection is available.
android.vending.CHECK_LICENSE
This permission is used for license validation if you bought the app at the google market.
android.permission.MANAGE_ACCOUNTS and android.permission.GET_ACCOUNTS and android.permission.AUTHENTICATE_ACCOUNTS and android.permission.WRITE_SYNC_SETTINGS
The app can create custom calendars. To prevent automatic cleanup services from android from deleting this custom calenders these calendars must be assigned with an existing sync account. The permissions above will be used to create such a dummy sync account.