Rorate Caeli is reporting that Le Figaro has an interview with Vatican Secretary of State Cardinal Bertone confirming the expected Motu Proprio. You don’t get better confirmation than this.
The publication of the motu proprio which specifies this authorisation will take place, but it will be the pope himself who will explain his motivations and the framework of his decision. The Sovereign Pontiff will personally explain his vision for the use of the ancient Missal to the Christian people, and particularly to the Bishops.
So this is the Pope’s baby and he is handling it himself. Is the letter that will accompany the Motu Proprio the full explanation, or will there be more?