regression in host_name field introduced in v6.1
I hoped this gets clarified or becomes obsolete due to other tickets (legacy/trac#26864 (moved)) but since there is no progress I'll file it separately for onionoo.
Before v6.1 got deployed the host_name field for most relays contained an actual hostname (not just IP), now (with v6.1) all but less than 10 relays only show an IP address. The verified_host_names field does not appear to match the host_name field.