exitaddresses, and bulkexitlist, (and check?), don't know about IPv6
https://check.torproject.org/cgi-bin/TorBulkExitList.py?ip=220.127.116.11&port=80 gives me a pile of ipv4 addresses. I think it parses https://check.torproject.org/exit-addresses plus maybe descriptors or consensuses to get exit policies.
But tordnsel was written back when IPv6 was not a thing. So that means every step of our pathway is missing the concept of IPv6.
I guess the most urgent part to fix, which ties into metrics, is that we aren't collecting the ipv6 exit addresses of relays, which means we won't be able to look back in time and answer questions that have to do with ipv6 connections out of Tor.