The Well-Known Prefix MUST NOT be used to represent non-global IPv4 addresses, such as RFC1918

[momoka0122y]

This was dismissed on #18 but today I just found it in RFC6052. (I didn't notice this until now since i was only reading RFC7050 and RFC6146)

[3.1](https://datatracker.ietf.org/doc/html/rfc6052#section-3.1).  Restrictions on the Use of the Well-Known Prefix

   The Well-Known Prefix MUST NOT be used to represent non-global IPv4
   addresses, such as those defined in [[RFC1918](https://datatracker.ietf.org/doc/html/rfc1918)] or listed in Section 3
   of [RFC5735].  Address translators MUST NOT translate packets in
   which an address is composed of the Well-Known Prefix and a non-
   global IPv4 address; they MUST drop these packets.

If you think this part is not necessary because it is already documented here I understand, but I think it is very informational if it is in this document. (As I did not know this was a MUST NOT until today)