Father,
Thank you.
From the look of the altar, which appears set up for the ad-orientem sacrifice, I would venture to say that it is the Novus Ordo Mass, since I cannot make out any Mass cards.
Also, the Sacrificing priest seems to be seated facing the nave, unlike the Gregorian Rite where the priest sits at the side and faces the altar of sacrifice.
Deo Gratias!

Dan,
Well, like all Roman Catholic Churches they celebrate the Latin Rite, hopefully in both the Extraordinary and Ordinary forms.
I can't tell from the picture if it is a Mass celebrated in the Ordinary Form celebrated Ad Orientem or if it is the Extaordinary Form. In Rome it is not uncommon to see the Ordinary Form celebrated Ad Orientem,so it could be either one.

I've got photo from this chapel in Saint Mary Major too. I was bummed that I could not attend the mass at the chapel but my tour group would have left me behind.

Fr Christensen,
Does that church offer the Gregorian Rite of Holy Mass?

It is the Marian Chapel containing the miraculous icon called Salus Populi Romani in Saint Mary Major in Rome. Furthermore, the little friar serving the Mass is a Franciscan Friar of the Immaculate who take care of that particular church.

Perhaps the Papally erected church that has been given to the FSSP to exclusively offer the Gregorian Rite of the Holy Sacrifice of Mass: the Church of Ss. Trinita dei Pellegrini?
Your best mystery photo to date anyhow.

Cinecittà studios in Rome?