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GNU Free Documentation License

GNU Free Documentation License
GFDL Logo.svg
The GFDL logo
Author Free Software Foundation
Latest version 1.3
Publisher Free Software Foundation, Inc.
Published Current version:
November 3, 2008
DFSG compatible Yes, with no invariant sections (see below)
FSF approved Yes
GPL compatible No
Copyleft Yes

The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free documentation, designed by the Free Software Foundation (FSF) for the GNU Project. It is similar to the GNU General Public License, giving readers the rights to copy, redistribute, and modify (only when without "invariant sections" restrictions) a work and requires all copies and derivatives to be available under the same license. Copies may also be sold commercially, but, if produced in larger quantities (greater than 100), the original document or source code must be made available to the work's recipient.

The GFDL was designed for manuals, textbooks, other reference and instructional materials, and documentation which often accompanies GNU software. However, it can be used for any text-based work, regardless of subject matter. For example, the free online encyclopedia uses the GFDL (coupled with the Creative Commons Attribution Share-Alike License) for all of its text.

The GFDL was released in draft form for feedback in September 1999. After revisions, version 1.1 was issued in March 2000, version 1.2 in November 2002, and version 1.3 in November 2008. The current state of the license is version 1.3.

The first discussion draft of the GNU Free Documentation License version 2 was released on September 26, 2006, along with a draft of the new GNU Simpler Free Documentation License.

Material licensed under the current version of the license can be used for any purpose, as long as the use meets certain conditions.

The license explicitly separates any kind of "Document" from "Secondary Sections", which may not be integrated with the Document, but exist as front-matter materials or appendices. Secondary sections can contain information regarding the author's or publisher's relationship to the subject matter, but not any subject matter itself. While the Document itself is wholly editable, and is essentially covered by a license equivalent to (but mutually incompatible with) the GNU General Public License, some of the secondary sections have various restrictions designed primarily to deal with proper attribution to previous authors.


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