The Android Marshmallow lets the users control the permissions each app request and revoke each of them. To manage app permissions on Nexus 6P and other Android devices running the Android 6 Marshmallow, do as follows:
1. Open the Settings application
2. Tap the Apps option under the Device settings
3. Now you should see the list of your application installed on your device
4. Tap the application you want to manage the permission, to see the app's details
5. And now tap the Permissions option to see the app's permissions
6. Simple tap each permission to revoke it. For example, tap the Location permission and turn it off, so the application won't be able to use your location any more.
** Note that revoking permissions for applications, may cause them malfunction.