I'm confused. Didn't the Vatican already give a universal indult that was ignored by many bishops? How does this change the landscape? Would the pope demand accountability or would the 'universal indult' now be celebrated in SSPX Chapels?
No. The current status is that Rome has said the Mass is to be encouraged by the local Ordinary for those faithful who desire the Mass using the 1962 Missal but it is not granted a Universal Indult. Many Dioceses have no Tridentine Mass or one which is offered only occasionally.
The status here would be that all chapels and seminaries owned or run by the SSPX would be in full communion with Rome. The details of all this is what is to be discussed and would probably be akin to the Campos situation. Thus, Masses offered at these sites are then fully valid for any and all.
If you call the local Diocese now and ask if an SSPX Mass is valid, they will tell you it does not fulfill your Sunday obligation. I don't wish to get into that discussion but it would no longer be the case if this is guided by the Holy Spirit and resolved.