Bukkit Page (Original plugin): http://dev.bukkit.org/bukkit-plugins/chest-commands
Spigot Page (Forked plugin): https://www.spigotmc.org/resources/chest-commands-gui-forked.69014/
Chest Commands is free software/open source, and is distributed under the GPL 3.0 License. It contains third-party code, see the included THIRD-PARTY.txt file for the license information on third-party code.