In marshmallow's runtime permission, user can choose "never ask again" in permission requests. In this case, we have to redirect user to app settings to let them enable the permissions for the app. Also, Android permissions are group based, it will be very handy to display names of the permission groups that the app needs before we send the user to the settings.
I've seen the strings in android.Manifest such as "android.permission-group.LOCATION". Is it possible to get the permission group names programmatically?