ErfurtWiki is a wiki software written in PHP that is mostly released into the public domain. It is designed to be easy to integrate into existing websites and has a very powerful plugin system which handles almost all of its functional features. There are hundreds of plugins available.
It is an older wiki software that influenced later wiki implementations. The wiki part of the popular e-learning software platform Moodle is a fork of ErfurtWiki, for example. The name ErfurtWiki is derived from the name of the Thuringian capital Erfurt.
The wiki engine has a well structured code base. It has support for image uploads and saves its contents into a filesystem or database backend.
Most of the source code is public domain, some GNU GPL and GNU LGPL but there is also proprietary freeware (plugins/lib/js.php).
- LICENSE file in the tarball