Eternal Lands

Home: http://www.eternal-lands.com/
Media: https://en.wikipedia.org/wiki/Eternal_Lands
State: mature
Download: http://www.eternal-lands.com/page/download.php
Keyword: role playing, multiplayer online + massive
Code repository: https://github.com/raduprv/Eternal-Lands.git (@created 2011, @stars 103, @forks 51)
Code language: C, C++
Code license: Custom (modified QTPL: https://raw.githubusercontent.com/raduprv/Eternal-Lands/master/eternal_lands_license.txt)
Developer: Alexander Gottwald, bendoughty, Bruno Ramos, Felix Janda, gamil-zirak, Gé Vissers, Joe "Flame" Sullivan, Karol, "Paul Broadhead (bluap in EL)", Sir-Odie, xaphier

Is only the client open source? What about the server?

Building