The source code from mineplex 2018 leak with commit history dating back to 2014, it requires a lengthy setup to get functional but is a reasonably easy compile if you know what your doing just have to repatch the spigot

Chiss b74c11cd36 Minor text hub changes		2013-08-31 18:57:33 +10:00
Maps	Bob wants to play!	2013-08-29 15:55:49 +10:00
Nautilus.Core.VoteHub	Initial Commit	2013-08-27 08:14:08 -07:00
Plugins	Minor text hub changes	2013-08-31 18:57:33 +10:00
TestApps/LOCTester	Initial Commit	2013-08-27 08:14:08 -07:00
TexturePack	Initial Commit	2013-08-27 08:14:08 -07:00
Webserver/ServerHandler	Initial Commit	2013-08-27 08:14:08 -07:00
Website	Added LobbyBalancer for BungeeCord	2013-08-30 01:36:55 -07:00