Open-source license
They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications.
[4] Most countries, including the United States (US), have created copyright laws in line with the Berne Convention with slight variations.
[11] At that time, American activist and programmer Richard Stallman was working as a graduate student at the MIT Computer Science and Artificial Intelligence Laboratory.
[15][16] Two active members of the free software community, Bruce Perens and Eric S. Raymond, founded the Open Source Initiative (OSI).
[18] The DFSG were drafted to provide a more specific and objective standard for the FOSS that Debian would host in their repositories.
[21] Historically, these three organizations and their sets of criteria have been the notable authorities in determining whether a license covers free and open-source software.
Copyleft can be further divided into strong and weak depending on whether they define derivative works broadly or narrowly.
Patent claims give the holder the right to exclude others from making, using, selling, or importing products based on the idea.
[43] The US Supreme Court described using trademark law to restrict public domain content as "mutant copyright".
[44] In Dastar Corp. v. Twentieth Century Fox Film Corp., the court "caution[ed] against misuse or over-extension of trademark" law without providing a firm decision on those mutant copyrights.
Berkeley made these concepts explicit with clear disclaimers for liability and warranty along with conditions, or clauses, for redistribution.
[51][52] The Massachusetts Institute of Technology (MIT) created an academic license based on the BSD original.
Explicitly making covered code sublicensable provides a legal advantage when tracking the chain of authorship.
Version 2, published in 2004, offers legal advantages over simple licenses and provides similar grants.
[63] The term and its related slogan, "All rights reversed", had been previously used in a playful manner by the Principia Discordia and Tiny BASIC; the modern usage begins with Richard Stallman's efforts to create a free operating system.
[71] Both movements and their formal definitions require the covered work to be made available with source code and with permission for modification and redistribution.
[74] For example, Netscape drafted their own copyleft terms after rejecting permissive licenses for the Mozilla project.
The GPL, and the Affero License (AGPL) based on it, use a broad scope to describe affected works.
[85] In a pair of early lawsuits—Jacobsen v. Katzer in the United States and Welte v. Sitecom in Germany—defendants argued that open-source licenses were invalid.
[97] In a similar 2021 case, the US Supreme Court permitted the recreation of an API in a transformative product under fair use.
[100] Non-profit organizations like FSF and the Software Freedom Conservancy offer to hold the rights to developers' projects to enforce compliance.
[104] According to attorney Lawrence Rosen, copyright laws were not written with the expectation that creators would place their work into the public domain.
Highly permissive licenses described as "public domain" may legally function as unilateral contracts that offer something but impose no terms.
This creates the possibility that an outside party could attempt to control a public domain work via patent or trademark law.
[111][112] Proprietary software has heavily integrated open-source code released under the Apache, BSD, and MIT licenses.
[115][116] Weak copyleft licenses impose specific requirements on derivative works that may allow the covered code to be distributed within proprietary software in certain circumstances.
[77] Cloud computing relies on free and open-source software and avoids the distribution that triggers most licenses.
[118] The copyleft GNU Affero General Public License (AGPL) is triggered when covered code is hosted or distributed.
[117] Developers have criticized cloud companies that profit from hosting open-source software without contributing money or code upstream, comparing the practice to strip mining.
[123] Cloud computing leader Amazon Web Services has stated they comply with licenses and act in their customers' best interests.
