The Debian Free Software Guidelines (DFSG) are a concise set of criteria that the Debian Project uses to judge whether a software license qualifies as free. They form part of Debian's Social Contract and serve as a practical test for whether a package can be placed in Debian's "main" archive. Beyond Debian, the DFSG have been influential in discussions about open source and free software licensing.
Core principles and typical criteria
The DFSG emphasize freedoms rather than technical features: the right to redistribute, access to source code, permission to make and distribute derived works, and the absence of discrimination against people, groups, or fields of endeavor. They also require that a license apply to all to whom the program is redistributed and not be tied to Debian specifically. In practice these principles guide how Debian evaluates real licenses.
- Freedom to redistribute and sell copies.
- Availability of source code.
- Permission to modify and distribute modifications.
- No discrimination against persons, groups, or fields of use.
- Licenses must not be specific to Debian or extend restrictions to other software.
History and development
The DFSG were drafted in the early life of the Debian Project as a statement of values and a practical tool to decide which software belongs in the project's main distribution. They were written as part of a broader Social Contract that explains Debian's commitments to free software and users. Over time the guidelines have been applied to many licenses and have shaped community expectations around what constitutes a free license.
Uses, impact, and examples
Debian maintainers and licensing teams apply the DFSG when packaging software: licenses that meet the DFSG are eligible for inclusion in the main archive, while software that does not comply may be placed in "contrib" or "non-free" sections or excluded. The DFSG also influenced the Open Source Definition and are frequently cited in debates about whether particular licenses or license clauses are compatible with free software principles.
Limitations and notable distinctions
The DFSG are a policy guideline, not a substitute for legal advice. They describe what Debian considers to be "free" in a practical, distribution-management sense and sometimes require interpretation for new or complex licenses. Legal compatibility, enforceability, or differences between jurisdictions are separate issues that may require legal analysis beyond the DFSG's scope.
As a result, the DFSG remain an important community standard: they provide clarity for Debian packaging, influence broader open source norms, and offer a clear, values-based checklist for evaluating licenses while leaving room for discussion and careful interpretation when novel licensing questions arise.