MsgPack is written mostly by Sadayuki Furuhashi and Takatoshi Kondo and
released under ths Boost Software License, Version 1.0

The MsgPack website contains a copyright footer

    Copyright © 2008-2013 Sadayuki Furuhashi

The included header files for msgpack-c, version 1.4.2 contains copyright
notices which can be aggregated (via grep, sort, uniq and minor manual
editing to create per-author supersets) to

Copyright (c) 2008-2015 FURUHASHI Sadayuki and KONDO Takatoshi
Copyright (c) 2008-2012 Rene Rivera 
Copyright (c) 2002-2012 Paul Mensonides
Copyright (c) 2002 Anthony Ventimiglia
Copyright (c) 2011-2014 Edward Diener
Copyright (c) 2013 Vladimir Volodko
Copyright (c) 2014 Microsoft Corporation
Copyright (c) 2014 Franz Detro
Copyright (c) 2014 Jessica Hamilton 
Copyright (c) 2015 MIZUKI Hirata
Copyright (c) 2015 Charly Chevalier
Copyright (c) 2015 Joel Falcou