3.1.0 is a release file of the Minecraft plugin Plot², made for Minecraft 1.5.0, 1.8.1. It was published on August 19, 2015 and is 1.2 MB in size. For the full description, screenshots and every other version, visit the Plot² plugin page.
How to install: Put the .jar into the plugins folder of your Paper, Spigot or Bukkit server and restart the server.