For example, the names of Mary’s parents, Ann and Joachim, that Joseph was significantly older than Mary was at the time of their engagement, and some of the details surrounding Mary’s life and the infancy of Jesus.
While the Gospel of James, or Protoevangelium of James, is not canonical, that does not mean that the text does not contain any valid information at all. The contents of the Protoevangelium of James give us an idea of some of the stories that were circulating at the time of its writing regarding the Holy Family and Mary. While some of them, we know, are not accurate, some of them could be and that gives us new things to think about.
That said, the book’s non-canonical status means that nobody is required to accept the accuracy of the Protoevangelium of James if he or she does not want to.
EDIT: It is important that I add that there is no “doctrine” or dogma that comes out of the Gospel of James and that, because of the writing’s inherent inaccuracy by which the Church deemed it non-canonical, the text never could provide a substantial basis for the formulation of any infallibly defined Church teaching.