The 1300 year old codex mixes Orthodox Christian and Sethian traditions in it. The Sethian tradition is a group that idolized Seth, tthat 3rd son of Adam and Eve; it became a major Gnostic sect.
The designation gnosticism is a term of modern scholarship. It was first used by the English poet and philosopher of religion Henry More (1614–87), who applied it to the religious groups in ancient sources as gnostikoi (Greek: those who have gnosis, or “knowledge”).
The Greek adjective gnostikos (“leading to knowledge” or “pertaining to knowledge”) was first used by Plato to describe the cognitive or intellectual dimension of learning, as opposed to the practical. By the 2nd century ad, however, gnostikoi had been adopted by various Christian groups, some of which used it positively as a self-designation, though others criticized this practice as a presumptuous claim of exclusive access to truth.