The GPL font exception clause (or GPL+FE, for short) is an optional clause within the GNU General Public License

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

 (GNU GPL) permitting digital fonts shared with that license to be embedded within a digital document

Document

The term document has multiple meanings in ordinary language and in scholarship. WordNet 3.1. lists four meanings :* document, written document, papers...

 file

Computer file

A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished...

 without requiring the document itself to also be shared with GPL. Without the clause, conflicts may arise with open source projects distributing digital fonts which may be used in desktop publishing. According to Terry Hancock, editor of Free Software Magazine

Free Software Magazine

Free Software Magazine is a website which produces a mostly free-content e-zine about free software....

, "There are some other free font licenses, but the GPL with the font exemption is the simplest and most compatible."

GPL+FE is a strategy for sharing open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 digital fonts comparable to the SIL Open Font License

SIL Open Font License

The SIL Open Font License is a free and open source license designed for fonts by SIL International for use with some of their Unicode fonts. The license is considered free by the Free Software Foundation, which states that a simple hello world program is enough to satisfy the license's requirement...

. As explained by Dave Crossland in Libre Graphics Magazine, "A copyleft

Copyleft

Copyleft is a play on the word copyright to describe the practice of using copyright law to offer the right to distribute copies and modified versions of a work and requiring that the same rights be preserved in modified versions of the work...

 font may overreach into the documents that use it, unless an exception is made to the normal terms; an additional permission to allow people to combine parts of a font with a document without effecting the license of texts, photographs, illustrations and designs. Most libre fonts today have such a copyleft license – the SIL OFL or GNU GPL with the Font Exception described in the GPL FAQ."

Origin

The font exception was authored in April 2005 by David "Novalis" Turner, a Free Software Foundation

Free Software Foundation

The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...

 GPL compliance engineer. As he explains, "The situation we were considering was one where a font was embedded in a document (rather than merely referenced). Embedding allows a document to be viewed as the author intended it even on machines that don't have that font installed. So, the document (a copyrighted work) would be derived from the font program (another work). The text of the document, of course, would be unrestricted when distributed without the font."

To be in compliance with the GPL, Red Hat

Red Hat

Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....

's Fedora Linux

Fedora (operating system)

Fedora is a RPM-based, general purpose collection of software, including an operating system based on the Linux kernel, developed by the community-supported Fedora Project and sponsored by Red Hat...

 project included the font exception with the license for its Liberation font package

Liberation fonts

Liberation is the collective name of four TrueType font families: Liberation Sans, Liberation Sans Narrow, Liberation Serif and Liberation Mono...

, albeit with additional restrictions in 2007. These restrictions prompted further discussion among the Debian GNU/Linux distribution's community members concerning the GPL+FE. This attention prompted Ubuntu

Ubuntu (operating system)

Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu...

 to follow suit and create Ubuntu Font License because they were satisfied with neither the SIL OFL nor with GPL+FE.

Usage

To indicate a font exception to the GPL, a digital font creator adds the following language to the end of the GPL text distributed with their font:

"As a special exception, if you create a document which uses this font, and embed this font or unaltered portions of this font into the document, this font does not by itself cause the resulting document to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the document might be covered by the GNU General Public License. If you modify this font, you may extend this exception to your version of the font, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version."