The APN framework is described in this https://datatracker.ietf.org/doc/draft-li-apn-framework/, while the APN Header and its encapsulation in the IPv6 data plane are described in both https://datatracker.ietf.org/doc/draft-li-apn-header/ and https://datatracker.ietf.org/doc/draft-li-apn-ipv6-encap/. To further clarify the differences between the existing IETF work and the APN work, there is also this gap analysis draft https://datatracker.ietf.org/doc/draft-peng-apn-scope-gap-analysis/ for people’s reference.