Most people in the comments missing the point here: Luther didn’t remove books from the Bible and Trent didn’t add them. Before Trent and its addition of the anathema clause it was always an open conversation. The 66 is what everyone agreed upon, the question was about the apocrypha (a term not invented by but clarified on by Athanasius in his 39th Festal Letter in AD 367 to describe the other books of the OT outside of the 39). If the 73 canon was, as many in the comments to my OP want to reductionistically claim, a settled issue going back centuries then you wouldn’t have the Jeromes, Athasiuses, Cyrils, Gregory the Greats, Ximenes, and Cajetans of the world all openly discussing and disagreeing with various Deuterocanonicals and their inclusion vs. exclusions as inspired canon. These aren’t randoms, they’re Saints, Bishops, Popes, Cardinals, and Doctors of the Church.
I think a lot of people would be surprised to hear how close the vote on their inclusion in an official list attached to an anathema was at Trent. At the Council of Trent, considerable debate took place on whether a distinction should be made between two classes of books (canonical and apocryphal) or whether three classes should be identified (Acknowledged Books; the Disputed Books of the New Testament, later generally received; and the Apocrypha of the Old Testament). Finally on 8 April 1546, by a vote of 24 to 15, with 16 abstensions, the Council issued a decree (De Canonicis Scripturis) in which, for the first time in the history of the Church, the question of the contents of the Bible was made an absolute article of faith and confirmed by an anathema.
Prior to the Council of Trent in 1545 there was no such thing as an agreed upon “Roman Catholic Bible.” Cardinal Ximenez (who died in 1517 - the very year Martin Luther nailed his 95 Thesis to the Castle Church door in Wittenberg) in the preface to his Complutensian Polyglot Bible described the 7 books of the Deutercanon as “books outside the canon.” He explains that their purpose is to be “received by the Church rather for the edification of the people than for the authoritative confirmation of ecclesiasitcal doctrines.” In essence, Ximenes’s position was: valuable and edifying for Christians, but outside the primary canon and insufficient by themselves to establish doctrine.