Hi, is the specification not up-to-date in regards of hostname resolution?
6.4. Remote hostname lookup ... **For backward compatibility, if there are any IPv4 answers, one of those** ** must be given as the first answer.**
However, if you connect to a dual stack web service via Tor Browser, the connection will be IPv6, if the exit node supports it. Have I missed something?
For streams the specification also states IPv4 as default:
6.2. Opening streams and transferring data ... bit meaning 1 -- IPv6 okay. We support learning about IPv6 addresses and connecting to IPv6 addresses. 2 -- IPv4 not okay. We don't want to learn about IPv4 addresses or connect to them. 3 -- IPv6 preferred. If there are both IPv4 and IPv6 addresses, we want to connect to the IPv6 one. (By default, we connect to the IPv4 address.)