[nsd-users] What is the selection order of forward-first NSs? sequential? random? IPv6 before/after IPv4?

[PGNet Dev]

On my server, I config

	cat /etc/resolv.conf
		nameserver 127.0.0.1

, where unbound 1.13.1 listens @

	server:
		interface: 127.0.0.1 at 53

if I set up forward-first in unbound config,

	forward-zone:
		name: "."
			forward-first: yes
			forward-addr: <server.1.ipv.6>
			forward-addr: <server.1.ipv.4>
			...
			forward-addr: <server.n.ipv.6>
			forward-addr: <server.n.ipv.4>

what's the order policy for those forward-addr's?

Is the forward-addr used randomly, or sequentially, selected from that list?

Is there any unbound preference for IPv4 vs IPv6 forward-addrs?
Does the preference respect /etc/gai.conf?