37 For the rest, far from its being the mind of the Apostolic See to damage the integrity or hinder the preservation of this rite, it rather caused the Ruthenian Church to cherish most religiously the traditions in liturgical matters handed down from antiquity. An outstanding sign of this zealous favor towards the Ruthenian rite may be seen in the new Roman edition of its liturgical books begun in our pontificate and already in part happily accomplished. In this edition the Apostolic See, gladly assenting to the wishes of the Ruthenian bishops, has endeavored to restore their liturgical rites in accordance with their venerated ancient traditions.
Source: Orientales Omnes Ecclesias (Vatican.va)