n/dns.md: remove the long comment containing the old version of ECS

n/dns.md

@@ -157,54 +157,6 @@ See also:
 - [AdGuard DNS: Privacy-friendly EDNS Client Subnet](https://adguard-dns.io/en/blog/privacy-friendly-edns-client-subnet.html)
 - [DNS0 Privacy Policy](https://www.dns0.eu/privacy)
 
-<!--
-
-[_Understanding the Privacy Implications of ECS_](https://yacin.nadji.us/docs/pubs/dimva16_ecs.pdf)
-brings up two bigger issues EDNS client-subnet:
-
-- Authoritative nameserver is given part of the subnet, which can be
-  personally identifiable and as the connection between recursor and
-  authoritative is unencrypted, anyone between them can observe all the
-  queries.
-  - Think of VPNs where traffic within the VPN is encrypted, but it won't
-    magically encrypt plain traffic leaving it.
-  - The part given to the au4thoritative nameserver is `/24` on IPv4 and
-    `/56` on IPv6. These equal 192.0.2.x so if a MITM wanted to know who you
-    are there would be 254 options (assuming there are no NATs). On IPv6 a
-    `/56` includes 256 `/64` blocks and `/64` is the most used block and there
-    is a recommendation of giving customers a `/56` block, so it would point
-    directly to your connection. However some mobile operators give a `/64`
-    so it will again point to 256 options again. Not that many.
-- Anyone between the recursive and authoritative nameservers can perform cache
-  poisoning attack and give it a narrow target. With short TTL, it may be
-  impossible to audit afterwards. Only DNSSEC can protect from this, but
-  DNSSEC signing isn't used that widely.
-
-These issues bring additional questions:
-
-- Do you care?
-  - If you run open wireless network and offer everyone ECS nameserver such as
-    Google DNS through DHCP while using manually configured encrypted DNS by
-    yourself, is there any cause for concern? You can always say it was
-    someone using your open network? Or if this is a multi-user system like
-    VPS running titlefetcher bot or Matrix homeserver, who knows who triggered
-    the original queries and where? SteamOS? Speed over all as it's only used
-    for gayming. Virtual machine lab? Who cares. Larger organization? That may
-    be a big target?
-  - How much does getting local content matter to you? More or less than
-    increased resource use of contacting a server further away? _Is private ECS
-    an option?_ ([r/resolv.tsv](/r/resolv.tsv))
-- What is the impact of domains you visit being surveilled?
-  - This page mentions cases like FFUpdater where the surveillance would
-    reveal that I interact with github.com and other sites it downloads apk
-    files from, which hardly matters, but how about you?
-- What is the impact of cache poisoning tailored to you?
-  - Everything is encrypted and TLS certificates wouldn't match so would you
-    continue to the wrong site regardless of the prompt, or decide something
-    is wrong and try again later. How about your users?
-
--->
-
 ### Identifying support for ECS
 
 Or what is being sent to the authoritative servers.