"Wesnoth" development is decentralized due to its free and open-source nature. The officially blessed campaigns and units bundled with the game download are often derived from content created by the community, somewhat differently from the user-generated content in proprietary games where such content, while available, is usually not incorporated into official builds of the game. The "Wesnoth" forums and wiki are used to develop new campaigns, including new unit types and story artwork. The game is able to download new campaigns from a central add-on server. Content featured on the official campaign server must be licensed under the GNU GPL, like the game itself.