do you want to issue a PR for that or raise an issue on Github and we'll see if it can be added, probably not in time for 18.7.1 though.
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 ether 02:73:82:ed:48:00 inet 192.168.1.254 netmask 0xffffff00 broadcast 192.168.1.255 inet6 fe80::1:1%bridge0 prefixlen 64 scopeid 0xa nd6 options=1<PERFORMNUD> groups: bridge id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15 maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200 root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0 member: igb1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 2 priority 128 path cost 55 member: igb3 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 4 priority 128 path cost 55 member: igb2 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 3 priority 128 path cost 2000000
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 ether 02:73:82:ed:48:00 inet 192.168.1.254 netmask 0xffffff00 broadcast 192.168.1.255 inet6 2a02:8010:6228:dd00:73:82ff:feed:4800 prefixlen 64 inet6 fe80::1:1%bridge0 prefixlen 64 scopeid 0xa inet6 fe80::273:82ff:feed:4800%bridge0 prefixlen 64 scopeid 0xa nd6 options=1<PERFORMNUD> groups: bridge id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15 maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200 root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0 member: igb1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 2 priority 128 path cost 2000000 member: igb3 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 4 priority 128 path cost 55 member: igb2 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP> ifmaxaddr 0 port 3 priority 128 path cost 2000000
After a succeful configuration of a Bridge Interface with a static IPv4 & IPv6 Addresses, I noticed that this Interface has no IPv6 link local, I could ping IPv6 internet sites from this Interface, but the Clients behind it don't get an IPv6 Address (the IPv6 configuration of this Interface goes with unmanaged RADV).