Essential freedoms^[2]

In order to be recognized as "free" under the Free Cultural Works definition, a license must grant the following freedoms without limitation:

• The freedom to use and perform the work: The licensee must be allowed to make any use, private or public, of the work. For kinds of works where it is relevant, this freedom should include all derived uses ("related rights") such as performing or interpreting the work. There must be no exception regarding, for example, political or religious considerations.
• The freedom to study the work and apply the information: The licensee must be allowed to examine the work and to use the knowledge gained from the work in any way. The license may not, for example, restrict "reverse engineering".
• The freedom to redistribute copies: Copies may be sold, swapped or given away for free, as part of a larger work, a collection, or independently. There must be no limit on the amount of information that can be copied. There must also not be any limit on who can copy the information or on where the information can be copied.
• The freedom to distribute derivative works: In order to give everyone the ability to improve upon a work, the license must not limit the freedom to distribute a modified version (or, for physical works, a work somehow derived from the original), regardless of the intent and purpose of such modifications. However, some restrictions may be applied to protect these essential freedoms or the attribution of authors.

Permissible Restrictions

Apart from the following allowed restrictions, the license must not include clauses which limit essential freedoms. Especially, it must not specify any usage restrictions, such as prohibiting commercial use of the work, or restricting use in a political or religious context.

• Attribution of authors: Attribution protects the integrity of an original work, and provides credit and recognition for authors. A license may therefore require attribution of the author or authors, provided such attribution does not impede normal use of the work. For example, it would not be acceptable for the license to require a significantly more cumbersome method of attribution when a modified version of the licensed text is distributed.
• Transmission of freedoms: The license may include a clause, often called copyleft or share-alike, which ensures that derivative works themselves remain free works. To this effect, it may for example require that all derivative works are made available under the same free license as the original.
• Protection of freedoms: The license may include clauses that strive to further ensure that the work is a free work, notably by enforcing some of the conditions specified in the next section, for example, access to source data, or prohibition of technical measures restricting essential freedoms.

Additional conditions

While adhering to the essential freedoms, a specific work may be non-free in other ways which restrict the essential freedoms. These are the additional conditions necessary for a work to be considered free:

• Availability of source data: Where a final work has been obtained through the compilation or processing of a source file or multiple source files, all underlying source data should be available alongside the work itself under the same conditions. This can be the score of a musical composition, the models used in a 3D scene, the data of a scientific publication, the source code of a computer application, or any other such information.
• Use of a free format: For digital files, the format in which the work is made available should not be protected by patents, unless a world-wide, unlimited and irrevocable royalty-free grant is given to make use of the patented technology. While non-free formats may sometimes be used for practical reasons, a free format copy must be available for the work to be considered free.
• No technical restrictions: The work must be available in a form where no technical measures are used to limit the freedoms enumerated above.
• No other restrictions or limitations: The work itself must not be covered by legal restrictions (patents, contracts, etc.) or limitations (such as privacy rights) which would impede the freedoms enumerated above. A work may make use of existing legal exemptions to copyright (in order to cite copyrighted works), though only the portions of it which are unambiguously free constitute a free work.