Mozilla’s software is open source. This means that the software is not only available for download free of charge, but you have access to the source code and may modify and redistribute our software subject to certain restrictions as detailed in the Mozilla Public License. Official binary releases from the Mozilla Foundation are also released under the Mozilla End-User License Agreement.
Our code is free, but we do strictly enforce our trademark rights, we must, in order to keep them valid. Our trademarks include, among others, the names Mozilla, Firefox, Thunderbird, Bugzilla and XUL, as well as the Mozilla logo, Firefox logo, Thunderbird logo and the red lizard logo. This means that, while you have considerable freedom to redistribute and modify our software, there are tight restrictions on your ability to use the Mozilla name and logos, even when built into binaries that we provide.
For more information, please see: