Donatella Di Cesare has an article in both English and Italian on GA 97 of Heidegger’s Black Notebooks:
In line with his metaphysical anti-Semitism, Heidegger sees extermination as “self-destruction”. In 1942, he wrote that the Judenschaft, the “community of Jews”, is “in the age of the Christian West – the age of metaphysics – the principle of destruction”. A little further on he adds: “Only when what is essentially ‘Jewish’, in the metaphysical sense, combats what is Jewish is the peak of self-destruction in history reached”.
The Shoah is presented as playing a decisive role in the history of Being because it coincides with the “supreme fulfilment of technology”, which consumes itself after devouring everything else. In this sense, the extermination of the Jews represents the apocalyptic moment when that which destroys ends up destroying itself. As the peak of “self-destruction in history”, the Shoah makes possible the purification of Being.