Can you provide more details on that?
Sure. Reproduced from the French periodical Sous La Banniere, a "Motu Proprio" of Pope Pius XI delegated extraordinary powers to then Titular Bishop of Saigon, Ngo-Dinh-Thuc. It reads as follows -
Pius XI, Pope:
By the fullness of the power of the Holy Apostolic See, We appoint as our Legate Peter Martin Ngo-Dinh-Thuc, titular of Saigon, for boundaries known to Us, with all the necessary faculties.
Given at Rome from St. Peter's, the 15th day of March, 1938, in the seventeenth year of our Pontificate.
(signed) Pius XI, Pope
The significance or extent of these powers, identical with those conferred by the same Pope on the predecessor of Bishop Thuc 12 years earlier, Bishop d'Herbigny, S.J., were made explicit by the Pope himself, as quoted by Father Paul Lesourd in his book Le Jesuite Clandestin:
"Orally, the Holy Father detailed first of all, all the powers which he was giving, including the choice of priests to consecrate and to confer on them the episcopacy without their having need of pontifical bulls, nor therefore to give their signatures engaging themselves to conform to such under oath.
"Then, after having detailed at length verbally all the truly extraordinary powers, the Pope thus summed himself up very solemnly:
"In a word We grant you all the pontifical powers of the Pope himself, which are not by Divine Law incommunicable."
I have photocopies of both Moto Proprio(s) mentioned above.