MediaWiki is the open source software that powers InfraWiki. It is developed mostly by volunteers, and overseen by the non-profit Wikimedia Foundation.[1]
Other notable wikis powered by MediaWiki include Wikipedia, ProleWiki, Wikispooks, and KeyWiki.
It's encouraged that InfraWiki contributors find ways to support the ongoing development of MediaWiki, whether by contributing code to the project, or by donating to various development groups, such as Wikimedia Foundation.