The most famous person to be a peritus for the Second Vatican Council seems to be the man who became Pope Benedict XVI.
Now I will ask, why on earth a young man of 34 was appointed as an EXPERT theologian to the council itself?
Well, the answer is quite obvious: the people who were pressing for change-at-any-cost stacked the deck by appointing a lad who had hardly even started his academic career as a theologian.
While Father Joseph Ratzinger was young, he a peritus only for a bishop - not for the Church herself. More importantly, he was not suggesting the massive upheaval that Kung was suggesting.
How absurd to have a young man advise you on whether or not to up-end the fabric of the Church.
He was advertised as the the man who would be able to reconcile cutting-edge Catholic theology with Barth's cutting-edge Reformed theology and provide the basis for Christian reunion in the West.
They hadn't yet realized that he was a crank. Luckily, he is a supremely lazy crank.