From The Sacred Triduum Missal, published by Neri Publications and Opus Mariae Mediatricis:
This ceremony is sometimes referred to as the Mass of the Pre-Sanctified, because the Blessed Sacrament distributed to the faithful at Holy Communion, was (pre-)consecrated the day before. As the altar symbolizes Christ, it is entirely nacked until the time of the Solemn Collects. In three steps, the celebrant mounts the altar of Calvary, unveiling the cross of Christ for adoration at each step. This takes place after the reading of the lessons, the Passion of our Lord Jesus Christ according to St. John and the solemn Collects of intercession for the needs of the Church and the world. Today's liturgy concludes with the reception of Holy Communion by priest and faithful. The Mass of the Pre-Sanctified is not a Mass in the strict sense, given that no consecration of the Sacred Species takes place. This is so, no doubt, because the Church on this day wishes to concentrate on the historical act of our Lord's Passion and Death on the Cross. Its sacramental renewal in the Sacrifice of the Mass will resume at the Easter Vigil and Easter Sunday itself.