CLOT (custom ladder or tournament) is a framework that allows players to create their own automated ladders or tournaments that far exceed the capabilities of Warzone's built-in ones.
This is an open-source framework that's intended to be used by players who know how to code in Python. The framework provided is just a skeleton to get you started. It's expected that players creating their own CLOT will extend the framework to meet their needs.
Each CLOT is hosted as its own website, separate from warzone.com. This website manages the ladder/tournament -- it has full control over how games are created, the game's map and settings, how players are ranked, how the ranks are presented, etc. Players who want to join can go to this website to sign up with their Warzone account.
CLOT works by communicating to Warzone through the public APIs to create games and get updates on them. Players who create their own CLOT must be a Warzone member, however there are no restrictions on who can join and play in a CLOT.
The source code can be downloaded or contributed to on github at https://github.com/FizzerWL/CLOT
For documentation on how to get started, see Getting Started with CLOT
For help, post on the CLOT forum at https://www.warzone.com/Forum/f6-CLOT-Development