CBORはMessagePackにインスパイアされたと書かれている場所
CBOR is MessagePack. At least cbor-ruby started with the MessagePack sources. The story is that Carsten took MessagePack, wrote a standard and added some things he wanted, and called it something else.
Indeed, the RFC says so directly:
CBOR was inspired by MessagePack. MessagePack was developed and
promoted by Sadayuki Furuhashi ("frsyuki"). This reference to
MessagePack is solely for attribution; CBOR is not intended as a
version of or replacement for MessagePack, as it has different design
goals and requirements.