http://ftpfaudev4triw2vxiwzf4334e3mynz7osqgtozhbc77fixncqzbyoyd.onion/ripe.net/rfc/rfc8994.html
                                
                                
                                                                            Zones are a mechanism to support structured addressing of ACP addresses within the same /48 ULA prefix. ¶ The key words " MUST ", " MUST NOT ", " REQUIRED ", " SHALL ", " SHALL NOT ", " SHOULD ", " SHOULD NOT ", " RECOMMENDED ", " NOT RECOMMENDED ",
    " MAY ", and " OPTIONAL " in this document are to be interpreted as
    described in BCP 14 [ RFC2119 ] [ RFC8174 ] when, and only when, they appear in all capitals, as shown here. ¶ 3.