Let’s start with Chapter V, “The Arrangement and Ornamentation of Churches for the Celebration of the Eucharist.”
Over the next several posts, we’ll look at general principles (288-294), the arrangement of the sanctuary (295-310) and the nave (311-318)
288. For the celebration of the Eucharist, the People of God are normally gathered together in a church or, if there is no church or if it is too small, then in another respectable place that is nonetheless worthy of so great a mystery. Therefore, churches or other places should be suitable for carrying out the sacred action and for ensuring the active participation of the faithful. Moreover, sacred buildings and requisites for divine worship should be truly worthy and beautiful and be signs and symbols of heavenly realities.*
*Cf. Sacrosanctum Concilium 122-124; Presbyterorum Ordinis 5; Inter Oecumenici 90: Eucharisticum Mysterium 24; Canon Law 932 §1.
The Church keeps tight tabs on this for the Sacrament of Marriage. Less so actually for the Eucharist. (Think homes, athletic venues, campgrounds, and the like.)
Well, the deep background of the tight tabs on location for Matrimony is the protection of women from kidnapping. That was not a concern with the Mass itself.
That being said, this is the key phrase here: “other places should be suitable for carrying out the sacred action and for ensuring the active participation of the faithful.”
I realize Rome has judged differently on occasion, but my own opinion is that this means a place where the faithful are not participating primarily by screens and PA systems. It means that new churches should avoid visual and, most especially, acoustical gigantism in their construction. I think stadiums and outdoor Masses of any significant scale are to burden the Mass unreasonably. Et cet.
I guess that the Cenacle site of the Last Supper either just squeaked by or has been grandfathered in.