Debian Free Software Guidelines

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The Debian Free Software Guidelines ( Debian Free Software Guidelines , or DFSG ) were created by the Debian Project to decide whether a software license is "free". The open source definition is based on the DFSG and is almost identical in terms of content and form. Furthermore, there are strong similarities in terms of content to the free software definition of the GNU project .


The DFSG has the following requirements:

  1. Unrestricted disclosure permission
  2. Availability of the source code
  3. Permission to modify the software and create derivative works.
  4. no discrimination against persons or groups of persons
  5. no restriction of the area of ​​application (e.g. commercial use)
  6. no restriction related to other programs
  7. the rights of the license apply to everyone (especially regardless of whether the software is redistributed as part of the Debian distribution or not)

All criteria are met by the GNU General Public License (GPL), the BSD license (2- and 3-clause) and the Artistic License .

Concept of freedom

The concept of freedom of the Debian project, as it is explained in the DFSG, essentially coincides with the concept of freedom of the Open Source Initiative (OSI) and the Free Software Foundation . However, Debian is stricter in interpreting licenses, so some licenses (such as the Common Development and Distribution License ) are considered free by OSI but not by Debian.

Debian Legal

The DFSG are only guidelines and not a legal text. The Debian-Legal mailing list provides advice on the interpretation of the DFSG . Some considerations from this list:

  • An author's promise to tolerate copyright infringement cannot replace a proper license. A later legal successor would not be bound by this promise ("Tentacles of Evil" test).
  • The license cannot require that the licensee notify the licensor of changes or the like. A user with a solar-powered notebook on a desert island could not meet this condition ("Desert Island" test).
  • To put it more precisely, the license may not require any contact to be made, since this would put politically persecuted people at a disadvantage (“dissident” test).

The decision as to whether a license is acceptable in the sense of the DFSG is ultimately made by the Debian FTP masters when checking newly submitted Debian packages.

Effects on Debian Distribution

Only software that meets these requirements will be included in the Debian distribution. As already mentioned, the authoritative interpretation of the DFSG is carried out by the subscribers to the debian-legal mailing list . The Debian ftpmasters make the final decision on whether to include a software package. In the case of controversial licenses, however, they normally follow the debian-legal mailing list.

There is also a non-free area (called "non-free") on the Debian servers that is maintained by the Debian project, but is not part of the distribution. This area ends up works that Debian has permission to distribute, but which do not meet the Debian Free Software Guidelines. This can be explained by the fact that there was no free graphical browser at the time these guidelines were issued. Since then there have been repeated efforts to abolish this area; in particular, the GNU Project urged it.

Following an amendment to the Debian Social Contract, these guidelines will in future not only be applied to computer programs, but to all content. As a result, since the “Sarge” release, non-free firmware, images and documentation have to be moved to the non-free area. The point documentation represents a particular problem: Whether the GNU Free Documentation License the DFSG met, is debatable. In a vote it was finally decided that as long as it has no unmodifiable sections, Debian will consider it free. Some GNU documentation is regarded by Debian as unfree and either distributed in the non-free area (including the documentation of tar ) or not at all.


The DFSG was preceded by the Free Software Foundation's Free Software Definition . The DFSG were written by Bruce Perens , former Debian Project Leader, and other Debian developers. They were first published in July 1997 along with the first version of the Debian Social Contract . The definition of open source , the Open Source Definition of the Open Source Initiative (OSI) , which follows a little later, is based on the DFSG .

Web links

Individual evidence

  2. MJ Ray: Re: Sofia SIP COPYRIGHTS. In: Debian. Software in the Public Interest, Inc., July 6, 2006, accessed January 25, 2009 .
  3. License information. Retrieved April 15, 2016 .
  4. DFSG and Software License FAQ (Draft). Retrieved April 15, 2016 .
  5. ^ Matthew Garrett: Roles and responsibilities of the FTPmaster team. February 19, 2005, accessed April 15, 2015 .
  6. Debian considers GNU FDL to be conditionally free. In: Debian. Software in the Public Interest, Inc., December 1, 2008, accessed January 25, 2009 .
  7. Package: tar-doc (1.16-1) [non-free]. In: Debian. Software in the Public Interest, Inc., accessed January 25, 2009 .
  8. Bruce Perens: Debian's “Social Contract” with the Free Software Community ”on the Debian announce mailing list