This plugin is no longer being supported by it's creator, Brett Flannigan.
This version of WorldBorder is currently maintained by DocW. Its source code can be found in the docwhomc/WorldBorder repository on GitHub. Join our Discord server WorldBorder Reboot.
Brett Flannigan's original WorldBorder plugin can be downloaded from its Spigot Resource page and its source code can be found in the Brettflan/WorldBorder repository on GitHub.