The Bragan rite has two Epistle readings for the Vigil of the Nativity: Is 62:1-4, followed by Rm 1:1-6 (which is the same as the Roman).
Concerning the matter of three readings in a primitive Roman rite or other rites, you may wish to read New Liturgical Movement, which touched on this subject some time ago (the first article can be found here).
The rubrics concerning the Gradual and Alleluia are different even though the texts are the same in both missals. In the Bragan Hodie scetis should be repeated up to the verse; however, should the Vigil fall on a Sunday, it should not be repeated, but the Alleluia is to follow immediately. The Roman only prescribes the Alleluia should the Vigil fall on a Sunday. This is due to the fact that, as we have been informed, the Vigil is a penitential day in the Roman missal.
Here are some of the differences in rubrics pertaining to the following day’s celebrations(which we have been informed of being common in local uses):
Matins are to be sung on the 24th, but after the Gospel follows the sung geneology of Jesus, then the Te Deum, the Collect, and Benedicamos Domino. Then follows the First Mass, at midnight. After the Communion antiphon the Et Verbum caro factum est responsory is said, immediately followed by Laudes (which is interpolated into the Mass, as happened during the Paschal Triduum in the Roman rite before the Pian reform in 1955).
The priest sings the first psalm’s antiphon, Natus est nobis hodie, and later on the antiphon of the Benedictus, Gloria in excelsis Deo. Having finished the Benedictus, then follows the usual Dominus vobiscum, then Post-communion, dismissal and Last Gospel. The rubrics also indicate that as three Masses will be celebrated on this day, with the traditional Last Gospel (In principio) being the reading of the third Mass, then the Gospel of the Epiphany, taken from St. Matthew, is to be used as the Last Gospel.
Finally, there are some indications on how to celebrate the Masses on Christmas Day when they are celebrated without sufficient interval for the Hours between them. The priest must always say the Ave Maria at the foot of the altar before the first Mass and during his confession, and is to commemorate our Lady with the Nesciens Mater (the Mass according to the Bragan usage always ends with a commemoration of the Virgin Mary) with the respective Last Gospel. During the second and third Masses the consecrated hosts from the first Mass are to be placed on the Epistle side of the corporal, but still within the corporal. It is advised that rubrics concerning time and place should be observed by Religious in the case of celebrating a Solemn Mass (contrasting with the exceptions for parishes).
We would like to the thank the author of the blog The Rad Trad for his help with the interpretation of the rubrics. Any lack of clarity in this post is a failure on our part to explain them properly, so should anyone wish any clarification please do not hesitate to e-mail us. We suggest all those interested in matters liturgical to stop by his website. The Rad Trad has done a series of posts on the Neo-Gallican Parisian Missal, which is well worth reading.