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Mozilla Code Licensing

Mozilla Public License

The Mozilla Foundation is the custodian of the Mozilla Public License (MPL), a open source/free software copyright license currently at version 1.1. There is a FAQ and an annotated version to help you understand it.

Mozilla Source Code

Core Mozilla project source code is licensed under a disjunctive tri-license giving you the choice of one of the three following sets of free software/open source licensing terms:

This allows the use of our code in as wide a variety of software projects as possible, while still maintaining copyleft on code we wrote. Some Mozilla projects have slightly different terms, as follows:

Tinderbox 1NPL (Netscape Public License) 1.1 or later
All other Perl webtools (e.g. Bugzilla, Tinderbox 2/3, Bonsai)MPL 1.1 or later
Rhino (JavaScript in Java)MPL 1.1 or later/GPL 2.0 or later

The mozilla/webtools directory in CVS contains independent projects under various different sets of terms. As a rule of thumb, Perl projects are MPLed and PHP projects are tri-licensed, but check carefully.

Any code checked into our CVS tree needs to comply with our licensing policy and should contain the appropriate license boilerplate text.

Mozilla Binaries

Branded binary releases are available under the following terms:

Firefox and ThunderbirdMozilla Corporation End-User Licensing Agreement
Camino, SeaMonkey and SunbirdMozilla Foundation End-User Licensing Agreement

Other binary releases are made available under the MPL.

You can also read various historical documents relating to the Mozilla and Netscape Public Licenses.

If, after reading all the above carefully (particularly the FAQ) you have a further question about the copyright licensing terms of Mozilla project code, please send it to