As a regular attendee of an Oratory of the Institute of Christ the King Sovereign Priest, the Votive Mass of Jesus Christ Eternal High Priest is very familiar to me, and is one of my favorites. In the Extraordinary Form it is one of the Votive Masses common to Thursdays, and there is a feast day local to Spain on the Thursday after Pentecost.
Thus I am glad to hear the news that Spanish Cardinal Canizares-Llovera, the Prefect of the Congregation for Divine Worship, is asking the Holy Father to extend this feast day to the universal Church. From New Liturgical Movement:
His Eminence Antonio Cardinal Cañizares Llovera, Prefect of the Congregation for Divine Worship and the Discipline of the Sacraments, announced this Monday his intention to ask the Holy Father, in this Year for Priests, to extend the Feast of Jesus Christ the Eternal High Priest (D.N.J.C. Summi et Æterni Sacerdotis) to the Entire Church (source: Religión Confidencial). The feast is currently celebrated in Spain on the Thursday after Pentecost by concession of Paul VI. The concession is from 1970, and had been petitioned for by the then Archbishop of Valencia José María García Lahiguera, the “Apostle of the Priests”, who helped the persecuted priests of Madrid during the Spanish civil war, founded in 1938 the Oblate Sisters of Christ the Priest dedicated to prayer and sacrifice for the sanctification of the priests, and whose process of beatification was opened in 1995.
A Mass de D.N.J.C. Summo et Æterno Sacerdote was first introduced, as a votive Mass for Thursdays, under Pius XI and announced in his Encyclical Ad Catholici Sacerdotii of 1935, and remains as such in the Missale Romanum of the Extraordinary Form. It is also contained as a votive Mass in the Roman Missal of the Ordinary Form. Fr Mark of Vultus Christi has a comparison of the two Mass formularies.