Here is a summary about Daniel 13-14 and why they were considered non-canonical by Protestants.
However the article from Bible.org is in error:
1 - It doesn't include the most famous of the apocryphal books, 1 Enoch.
2 - It misrepresents the church fathers when it way "none argued for canonization." Tertullian and others argued for 1 Enoch at least.
3 - It misrepresents OT quotes found in NT as "0" from apocryphal sources, passages from 1 Enoch are found in Gal., 1 Cor., and Jude.
So like anything on the internet take it with a grain of salt.
"Apocrypha, term coined by the 5th-century biblical scholar Saint Jerome for the biblical books received by the church of his time as part of the Greek version of the Old Testament (
see Septuagint), but not included in the Hebrew Bible.
Derived from the period 300 BC to New Testament times, the books of the Apocrypha included Judith, the Wisdom of Solomon, Tobit, Sirach (Ecclesiasticus), Baruch, and the two books of Maccabees. Also generally included with the Apocrypha are the two books of Esdras, additions to the Book of Esther (Esther 10:4-10), additions to the Book of Daniel (Daniel 3:24-90;13;14), and the Prayer of Manasseh."
https://bible.org/question/why-are-some-books-missing-kjv