There are two public statements, thus far, by the Emeritus Pontiff.
--The 1 September Vatican homily for the closing Mass of the Ratzinger Student Circle.
--The 3 September letter to the atheist journalist Piergiorgio Odifreddi, the full text in English in now on the National Catholic Register website.
The former is a reflection on humlity: on the grandeur of seeking the lowest place. The latter is a deep philosophical response to atheist bias, the full text of which is expected to be published with Odifreddi's new edition of his book to the Pope Emeritus.