Description says "Show IPv4 OSPF Graceful Restart" for OSPFv3 routing daemon
vyos@vyos:~$ show ipv6 ospfv3 Possible completions: <Enter> Execute the current command area Show Shortest Path First tree information border-routers Show OSPFv3 border-router (ABR and ASBR) information database Show OSPFv3 Link state database information graceful-restart Show IPv4 OSPF Graceful Restart