(config)> show running-config
! $$$ Model: ZyXEL Keenetic Giga II
! $$$ Version: 2.06.1
! $$$ Agent: http/rci
! $$$ Last change: Tue, 16 Jul 2019 06:32:07 GMT
! $$$ Md5 checksum: 446f15b38e231ae9075d9db684ae20bd
system
    ...
    set net.ipv6.conf.all.forwarding 1
    set net.ipv6.conf.all.accept_ra 1
!
...
interface UsbLte0
    description "USB LTE"
    usb device-id 12d1 1506
    usb apn internet
    security-level public
    ip address dhcp
    ip dhcp client dns-routes
    ip dhcp client name-servers
    ip global 16908
    up
!
interface Bridge0
    rename Home
    description "Home network"
    inherit GigabitEthernet0/Vlan1
    include AccessPoint
    mac access-list type none
    security-level private
    ip address 192.168.5.1 255.255.255.0
    ip dhcp client dns-routes
    ip dhcp client name-servers
    ipv6 address auto
    up
!
interface L2TP0
    description <hdden>
    role misc
    peer <hidden>
    ipv6cp
    lcp echo 30 3
    ipcp default-route
    ipcp name-servers
    ipcp dns-routes
    no ccp
    security-level public
    authentication identity <hidden>
    authentication password <hidden>
    authentication chap
    ip dhcp client dns-routes
    ip dhcp client name-servers
    ip mtu 1400
    ip global 49325
    ip tcp adjust-mss pmtu
    ipv6 address auto
    ipv6 prefix auto
    ipv6 name-servers auto
    ipv6 force-default
    connect via UsbLte0
    up
    bandwidth-limit 3621
!
...
ipv6 subnet HomeV6
    bind Home
    number 3
    mode slaac
!
ipv6 local-prefix default
ipv6 name-server 2001:4860:4860::8888 ""
ipv6 name-server 2001:4860:4860::8844 ""
ipv6 firewall
...

❯ ip -6 addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: enp5s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 fdb6:e163:9f30:3:e2a6:5615:57de:66a5/64 scope global dynamic noprefixroute
       valid_lft 4294966395sec preferred_lft 4294966395sec
    inet6 fe80::f23f:9eee:2abf:3cdd/64 scope link noprefixroute
       valid_lft forever preferred_lft forever
 ❯ ip -6 route
::1 dev lo proto kernel metric 256 pref medium
fdb6:e163:9f30:3::/64 dev enp5s0 proto ra metric 100 pref medium
fdb6:e163:9f30::/48 via fe80::ee43:f6ff:fe08:9400 dev enp5s0 proto ra metric 100 pref medium
fe80::/64 dev enp5s0 proto kernel metric 100 pref medium