Custom Ladder Or Tournament; it's a framework where you string together some Warlight APIs (Validate Token, Create Game, Query Game mainly) to create your own ladder/league/tournament.
You can find some boilerplate for that at:
https://github.com/FizzerWL/CLOTBetter boilerplate in some forked projects:
https://github.com/deadman1And the Warlight AI:
https://github.com/FizzerWL/WarLight.AIBut Warlight itself isn't open-source.