Who do you think wrote the books of the New Testament?
Do you differentiate between "wrote", "authored", and "inspired"?
CCC - 106 God inspired the human authors of the sacred books. "To compose the sacred books, God chose certain men who, all the while he employed them in this task, made full use of their own faculties and powers so that, though he acted in them and by them, it was as true authors that they consigned to writing whatever he wanted written, and no more."
Does it matter? Does it matter who wrote Hebrews? It has not mattered thus far. What matters is that the Church has declared it to be Canon.