So, a non-profit that skirts the rules, basically. Good to know.

It is a non-profit.

The Mozilla Corporation was established on August 3, 2005, to handle the revenue-related operations of the Mozilla Foundation. As a non-profit, the Mozilla Foundation is limited in terms of the types and amounts of revenue it can have. The Mozilla Corporation, as a taxable organization (essentially, a commercial operation), does not have to comply with such strict rules. Upon its creation, the Mozilla Corporation took over several areas from the Mozilla Foundation, including coordination and integration of the development of Firefox and Thunderbird (by the global free software community) and the management of relationships with businesses.