Monday, April 30, 2007

Licensing

Firefox is free/open source software, and is tri-licensed under the Mozilla Public License (MPL), GNU General Public License (GPL), and the GNU Lesser General Public License (LGPL). These licenses permit anyone to view, modify and/or redistribute the source code, and several publicly released applications have been built on it; for example, Netscape, Flock and Songbird make use of code from Firefox.

The official end-user builds of Firefox distributed from mozilla.com are licensed under the Mozilla EULA.[2] Several elements do not fall under the scope of the tri-license and have their use restricted by the EULA, including the trademarked Firefox name and artwork, and the proprietary Talkback crash reporter. Because of this and the clickwrap agreement included in the Windows version, the Free Software Foundation (FSF) consider these builds proprietary software.[40]

In the past, Firefox was licensed solely under the MPL,[41] which the FSF criticizes for being weak copyleft; the license permits, in limited ways, proprietary derivative works. Additionally, code under the MPL cannot legally be linked with code under the GPL or the LGPL.[42][43] To address these concerns, Mozilla re-licensed Firefox under the tri-license scheme of MPL, GPL, and LGPL. Since the re-licensing, developers have been free to choose the license under which they will receive the code, to suit their intended use: GPL or LGPL linking and derivative works when one of those licenses is chosen, or MPL use (including the possibility of proprietary derivative works) if they choose the MPL.[41]

[edit] Trademark and logo issues

The generic globe logo used when Firefox is compiled without the official branding
The generic globe logo used when Firefox is compiled without the official branding

The name "Mozilla Firefox" is a registered trademark; along with the official Firefox logo, it may only be used under certain terms and conditions. Anyone may redistribute the official binaries in unmodified form and use the Firefox name and branding for such distribution, but restrictions are placed on distributions which modify the underlying source code.[44]

To allow distributions of the code without using the official branding, the Firefox source code contains a "branding switch". This switch allows the code to be compiled without the official logo and name, for example to produce a derivative work unencumbered by restrictions on the Firefox trademark. In the unbranded compilation the trademarked logo and name are replaced with a freely distributable generic globe logo and the name of the release series from which the modified version was derived. The name "Deer Park" is used for derivatives of Firefox 1.5 and "Bon Echo" for derivatives of Firefox 2.0.

Outside of certain exceptions made for "community editions", distributing modified versions of Firefox under the "Firefox" name requires explicit approval from Mozilla for the changes made to the underlying code, and requires the use of all of the official branding. For example, it is not permissible to use the name "Firefox" without also using the official logo. The Debian project notably fell afoul of this, by using the name "Mozilla Firefox" but not the official logo, in a modified distribution (because of restrictions on its use, the Debian Free Software Guidelines did not permit Debian to use the logo). Although Debian claimed to have reached a prior agreement which would have allowed this, they were told in 2006 by a representative of the Mozilla Foundation that this was not acceptable, and asked to either comply with the published trademark guidelines or cease using the "Firefox" name in their distribution.[45] Ultimately, Debian switched to branding their modified version of Firefox as Iceweasel.

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