Mozilla is a free software community which produces the Firefox web browser. The Mozilla community uses, develops, spreads and supports Mozilla products, thereby promoting exclusively free software and open standards, with only minor exceptions. The community is supported institutionally by the Mozilla Foundation and its tax-paying subsidiary, the Mozilla Corporation. In addition to the Firefox browser, Mozilla also produces Thunderbird, Firefox Mobile, the Firefox OS mobile operating system, the bug tracking system Bugzilla and a number of other projects.