Editing Software license (section)

===Types of open-source licenses===
[[File:Open-source-license-chart.svg|thumb|alt=A pie chart displays the most commonly used open source license as Apache at 30%, MIT at 26%, GPL at 18%, BSD at 8%, LGPL at 3%, MPL at 2%, and remaining 13% as licenses with below 1% market share each.|The most popular open source licenses as of 2022 are the [[Apache License]] (permissive), the [[MIT License]] (permissive), and the [[GNU General Public License|GPL]] (copyleft).]]

*If software is in the [[public domain]], the owner's copyright has been extinguished and anyone may use the work with no copyright restrictions.{{sfn|O'Regan|2022|p=403}}
*Non-restrictive licenses allow free reuse of the work without restrictions on the licensing of [[derivative work]]s.{{sfn|Sen|Subramaniam|Nelson|2008|p=212}} Many of them require attribution of the original creators.{{sfn|Morin ''et al.''|2012|loc=Permissive versus Copyleft}} The first open-source license was a non-restrictive license intended to facilitate scientific collaboration: the [[Berkeley Software Distribution]] (BSD), named after the [[University of California, Berkeley]] in 1978.{{sfn|Smith|2022|loc=§&nbsp;3.2.1.1}}
*[[Copyleft]] licenses (also known as "share-alike"),{{sfn|Morin ''et al.''|2012|loc=Permissive versus Copyleft}} require [[source code]] to be distributed with software and require the source code be made available under a similar license.{{sfn|Sen|Subramaniam|Nelson|2008|pp=211-212}}{{sfn|St. Laurent|2004|pp=38-39}} Copyleft represents the farthest that reuse can be restricted while still being considered free software.{{sfn|Davila|2015|p=5}} Strong copyleft licenses, such as the [[GNU General Public License]] (GPL), allow for no reuse in proprietary software, while weak copyleft, such as the related [[GNU Lesser General Public License]] (LGPL), do allow reuse in some circumstances.{{sfn|Sen|Subramaniam|Nelson|2008|p=212}} Copyleft licenses are perceived by developers as a way of ensuring that their contributions do not create unfair advantages for others.{{sfn|Sen|Subramaniam|Nelson|2008|p=212}}{{sfn|Davila|2015|pp=5-6}} Another motivation for choosing  copyleft is to promote open source through its requirements for derivative works:{{sfn|Morin ''et al.''|2012|loc=Permissive versus Copyleft}} [[Richard Stallman|Stallman]] states that "the central idea of copyleft is to use copyright law, but flip it over to serve the opposite of its usual purpose: instead of a means of privatizing software, [copyright] becomes a means of keeping software free."{{sfn|Joy|2022|pp=990-992}} 

Outside of software, noncommercial-only [[Creative Commons]] licenses have become popular among some artists who wish to prevent others from profiting excessively from their work.{{sfn|Davila|2015|pp=5-6}} However, software that is made available for [[noncommercial]] use only is not considered open source.{{sfn|Davila|2015|p=6}} [[Sun Microsystems]]' noncommercial-only [[Java Research License]] was rejected by the open-source community, and in 2006 the company released most of Java under the GPL.{{sfn|Davila|2015|p=6}}