Take responsibility for your own projects and never expect other people to do your work for you. If they do help out take it as a bonus and be grateful.
Taurus, creator of Northern Rebirth, completer of Son of the Black Eye
There are cases where people involved with a Wesnoth add-on's development need to keep their work in sync with each other, keep track of the change history on their add-on, or simply need a secure back-up of their data.
The Coordinated Wesnoth UMC Development project (also known as Wesnoth-UMC-Dev) at SourceForge.net is aimed to solve these issues. The purpose of the Wesnoth-UMC-Dev project is to provide a shared repository for collaboration on Wesnoth UMC development. Having your project in this repo also means it will be periodically backed up, its change history will be preserved, and someone else can take it up if you abandon it.
Although we do not impose any quality standards in the add-ons hosted in the repository, it should be noted that the campaigns Legend of Wesmere, Delfador's Memoirs and Dead Water were once hosted in the repository to allow the mainline campaign maintainers to help the UMC developers to polish those campaigns and turn them into acceptable candidates for mainlining.
Other well-known add-ons hosted in the repository include the campaign Invasion from the Unknown, the Era of Strife and The Dark Hordes.
Please note that despite the involvement of some mainline developers in the project, the Battle for Wesnoth Project does not endorse, support or sponsor the Wesnoth-UMC-Dev Project directly.
There are many ways to help the Wesnoth-UMC-Dev project and the developers of its set of add-ons.
To bring some order to the initial chaos, it was required to establish some strict rules and soft guidelines upon what a developer may do, should do and must not do with his or her own add-on in the repository, or the rest of the repository. Remember that your liberty is limited by how much it can limit other people's liberty.