This describes open source projects or games with many primary developers.
In production and development, open source is a philosophy, or pragmatic methodology that promotes free redistribution and access to an end product's design and implementation details. Before the phrase open source became widely adopted, developers and producers used a variety of phrases to describe the concept; open source gained hold with the rise of the Internet, and the attendant need for massive retooling of the computing source code. Opening the source code enabled a self-enhancing diversity of production models, communication paths, and interactive communities. The open-source software movement was born to describe the environment that the new copyright, licensing, domain, and consumer issues created.
The open-source model includes the concept of concurrent yet different agendas and differing approaches in production, in contrast with more centralized models of development such as those typically used in commercial software companies. A main principle and practice of open-source software development is peer production by bartering and collaboration, with the end-product, source-material, "blueprints", and documentation available at no cost to the public. This is increasingly being applied in other fields of endeavor, such as biotechnology.
Source: Wikipedia, "Open source", available under the CC-BY-SA License.