GNU Free Documentation License
copyleft license primarily for free software documentation
The GNU Free Documentation License (GNU FDL or 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 (except for "invariant sections") 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 Wikipedia has much of its content licensed under the GFDL (coupled with the Creative Commons Attribution-ShareAlike License).
History
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.
On December 1, 2007, Wikipedia founder Jimmy Wales announced that a long period of discussion and negotiation between and amongst the Free Software Foundation, Creative Commons, the Wikimedia Foundation and others had produced a proposal supported by both the FSF and Creative Commons to modify the Free Documentation License in such a fashion as to allow the possibility for the Wikimedia Foundation to migrate the projects to the similar Creative Commons Attribution Share-Alike (CC BY-SA) license.
This brief starts where responsible research should: with the source description of “GNU Free Documentation License” as copyleft license primarily for free software documentation. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the science & nature register because the source frames it as copyleft license primarily for free software documentation. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Jun 20, 2026. The linked authority identifier is Q22169. 2 of 2 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1999, 2000, 2002 and 2008.
Scientific names, classifications and consensus can change while older terminology persists in catalogues and historical literature. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “GNU Free Documentation License”, its source revision and the description used here.
- Expand the search: follow GNU Free Documentation License primary sources, GNU Free Documentation License archive and Free research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “GNU Free Documentation License”?
- Which observation, specimen, dataset or publication supports the account?
- Is the terminology current, historical or disputed?
Search terms from this dossier
This entry incorporates text from “GNU Free Documentation License” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.