“That version incorporated a number of works that later, non-Hellenistic Jewish scholarship at the Council of Jamnia (AD 90)
identified as being outside the authentic Hebrew canon. The Talmud separates these works as Sefarim Hizonim (Extraneous Books),” according to
Britannica.
I have a low opinion of the Council of Jamnia, since it occurred after the schism between Judaism and Christianity, around the same time a malediction against heretics (by which were meant Christians and also Essenes, Beta Israel, followers of St. John the Baptist who did not accept Christ, and probably the Sadducees by that point, since they were marginalized by the Pharisees after the destruction of the Temple) was added to the litany known as Shemoneh Esreh (The Eighteen), which was until the addition of the aforesaid curse, a set of eighteen benedictions present in the Jewish liturgy that probably originated with St. Esdras (Ezra the Priest, who together with the Holy Prophet St. Nehemiah introduced the synagogue system and the reading of the Torah and Haftarah there, and at the Temple, to ensure Torah-literacy, which became the basis for Christian worship). I think some progressive Jewish congregations have dropped the malediction. At any rate, the Council of Jamnia was in all likelihood not aligned with Christian interests, given the period when it was held.
Now, this doesn’t mean we do everything the opposite of how Jamnia says to do it; some reactionary decisions like that have been made in the history of Christianity, some of which have been fine, such as the lack of fasting in Eastern Orthodoxy during the week following Septuagesima, which was a reaction against the Oriental Orthodox tradition of observing a severe fast called The Rogation of the Ninevites, a decision made at the Council of Trullo, or the Roman Catholic reaction to that same Council of Trullo, which they rejected, one canon of which prohibited depicting our Lord as a lamb; the reigning Pope responded by writing the hymn
Angus Dei and inserting it into the mass before the Communion. That last move actually resulted in some great liturgical music.
However, Jamnia is obviously not a Christian council, so my view is that we ought to pay no attention to it and not allow it to influence our thinking any more than we use the
Talmud for guidance on questions of moral theology or Old Testament exegesis. (Some Christians do enjoy reading the Talmud, and I’m actually one of them, because I find the Haggadah very enjoyable to read and filled with a surprising and clearly deliberate amount of Semitic humor, which is also present in the Old Testament and even in the Gospels; to love Jesus is to love the Jews and the Babylonian and Jerusalem Talmuds, while I reject it them as religious documents, are most definitely priceless Jewish cultural artifacts; I also have an interest in collecting Judaica, and want to start buying some of the more aesthetically interesting menorahs, etrog holders, and so on, and a dream of mine is to own a Torah scroll, which is also legitimate Christian Scripture.*
But in short, the Council of Jamnia is not relevant and any decisions about the legitimacy of the so-called Deuterocanonical Books, which I regard as Protocanon, specimens of most of which have been found in the Qumran Caves (the Dead Sea Scrolls), should be made by the Christian Church, for the Christian Church, based on what we think these texts say about Jesus Christ. The reason why I regard them as Protocanon is because most of them seem to have a very high density of Christological prophecies, a higher density than in some other OT books. This is also true of the longer versions of Esther and Daniel.
*Perhaps if I could acquire Torah Scrolls which had worn out and were no longer Kosher, which seems unlikely, as usually they are confined to a room set aside for storing such items; indeed at the Old Synagogue in Prague the repository for old Torah scrolls is in the attic, and legend has it the now-inanimate Golem is stored up there, and in a move I would find eerie if I believed in the Golem legend, the staircase to the attic was removed, but I only find it worrisome from a fire safety perspective, since an attic filled with old vellum scrolls and papyri seems like a bad idea).