Wireguard interfaces have IPv6 addresses that are auto-generated and cannot be disabled; note the two times I tried to tab complete:
[email protected]# set interfaces wireguard wg2 ipv6 Possible completions: > ospfv3 IPv6 Open Shortest Path First (OSPFv3) > ripng Routing Information Protocol (RIPng) [edit] [email protected]# set interfaces wireguard wg2 ipv6 add Configuration path: interfaces wireguard wg2 ipv6 [add] is not valid