There has to be one somewhere. In my case it's running on my router, but your ISP can do it at their end, and since you can use any /96 including public ones, it's also possible for anyone to run one:

  $ dig A +short github.com
  140.82.112.4
  $ dig AAAA +short github.com
  64:ff9b::8c52:7004
  $ dig AAAA +short github.com @2a01:4f8:c2c:123f::1
  2a01:4f8:c2c:123f:64:5:8c52:7004
  2a00:1098:2c::5:8c52:7004
  2a00:1098:2b::1:8c52:7004

  $ getent ahosts 2a00:1098:2b::1:140.82.112.4
  2a00:1098:2b::1:8c52:7004 STREAM 2a00:1098:2b::1:140.82.112.4