From Drupal and Moodle, right through to a Git versioning system and Perl modules on CPAN, we contribute back to over 175 community open source projects. This list is in order of the number of projects contributed to.
The GNOME project provides two things: The GNOME desktop environment, an intuitive and attractive desktop for users, and the GNOME development platform, an extensive framework for building applications that integrate into the rest of the desktop.
Heimdal Kerberos (http://www.h5l.org/)
Heimdal is an implementation of Kerberos 5, largely written in Sweden (which was important when we started writing it, less so now). It is freely available under a three clause BSD style license.
In-Folio is an easy to use, uniquely accessible e-portfolio application developed especially for use by and with learners with learning difficulties and disabilities. In-Folio is free software: you can redistribute it and/or modify it under the terms
Kete provides a platform for developing community contributed content. Kete allows uploading of different types of content: topics (html text based content), documents, audio files, images, movies and links. Kete is the māori word for basket, in the Kete system a basket is the overall organising structure for content. Beyond baskets content is organised by the community using tagging and relating pieces of content to each other. Kete is developed with Ruby on Rails, utilizes Zebra z39.50 full text indexing engine developed by IndexData, is fully compatible with Koha, and will be released under a GNU General Public License (GPL).
Libravatar is a service which delivers avatars to other websites. It implements the same API as Gravatar but adds DNS-based federation allowing domain name owners to host profile pictures for their own organisations. It also allows users to associate photos to their OpenID URLs, not just their email addresses.
Mahara user manual (http://manual.mahara.org)
The Mahara user manual is the user documentation for the ePortfolio and collaboration system Mahara (http://mahara.org). It is generated from rST files in Sphinx and translations are provided as well.
MaharaDroid enables Android phones to share or upload content to a Mahara instance. This app was superseded by Mahara Mobile for Android and iOS devices in October 2016.
Moodle (contrib) (http://cvs.moodle.org/contrib/)
This code is third-party or popular plugins, patches and tools for Moodle that are separate from the main codebase.
A rewrite of the Moodle question engine
Mozilla Core (http://www.mozilla.org/)
The core libraries shared by Mozilla applications.