Its publication could come "any day now," but until it hits print, Pope Benedict's repeatedly-delayed motu proprio on the celebration of the Tridentine Mass is much like the famous diary of the late Italian Cardinal Giuseppe Siri of Genoa: all that's known is that it exists... which makes any reportage on its contents difficult... but also of obsessive interest to many... if, for no other reason, because of the suspense factor. (Ironically enough, some adherents of the Old Mass maintain that Siri -- legendary for his conservatism, among other things -- had been elected to the papacy in the conclave...