RFC8781 defines a new RA (router advertisement) option called ‘PREF64’, which allows the switch to communicate the IPv6 prefix that is used for NAT64 to hosts on the network, via Router Advertisements. This feature adds support for configuring the PREF64 option on a per-interface basis. 

RFC4191 describes an optional extension to Router Advertisement messages for communicating default router

Nd RA RFC4191