Koha is an Open Source (GNU/GPL) Integrated Library System. The first version has been released in 2000, and Koha is now the most widely used library management software in the world.
The Koha community has more than 500 contributors from all around the globe (not counting translations and documentation)
The community is entirely self-managed: there is no foundation or legal entity behind Koha. As a (very) long-standing member of this community, I'll explain how this unorganized community is very organized !