A related question is can a relay with only an IPv4 address published currently set an IPv6 OutboundBindAddress?
Yes. This is useful for IPv6 exits without a fixed IPv6 ORPort address.
That's okay, but what if the node is an entry-and-middle node only?
Hmm. On second thought, it's *not* okay because it means that such a
node cannot be a middle node because it could only connect to the IPv6 universe. Or the man page is wrong about OutboundBindAddress. Or there is something else amiss.
"This option may be used twice, once with an IPv4 address and once with an IPv6 address"
T