The recordPacking parameter in 2.0 has completely different meaning than in 1.2. (See 13.2 copied below.) In short, it tells the server whether or not to take seriously the parameter recordSchema: if it is omitted or its value is 'packed' then the server MUST supply records according to the requested schema. If it is supplied with the value 'unpacked' then the server is free to choose an alternative schema.
Wow, this is confusing. I could understand repurposing an existing parameter if the new purpose was accurately summarised by the existing parameter name, but that doesn't seem to be the case here. I mean that the name 'recordPacking' does not intuitively suggest that the purpose is to say whether the server MUST return in the requested schema (or presumably return a diagnostic). Can someone explain the logic behind this choice?