<P> Despite initially accepting it, Richard Stallman of the FSF now flatly opposes the term "Open Source" being applied to what they refer to as "free software". Although he agrees that the two terms describe "almost the same category of software", Stallman considers equating the terms incorrect and misleading . Stallman also opposes the professed pragmatism of the Open Source Initiative, as he fears that the free software ideals of freedom and community are threatened by compromising on the FSF's idealistic standards for software freedom . The FSF considers free software to be a subset of open source software, and Richard Stallman explained that DRM software, for example, can be developed as open source, despite that it does not give its users freedom (it restricts them), and thus doesn't qualify as free software . </P> <P> When an author contributes code to an open - source project (e.g., Apache.org) they do so under an explicit license (e.g., the Apache Contributor License Agreement) or an implicit license (e.g. the open - source license under which the project is already licensing code). Some open - source projects do not take contributed code under a license, but actually require joint assignment of the author's copyright in order to accept code contributions into the project . </P> <P> Examples of free software license / open - source licenses include Apache License, BSD license, GNU General Public License, GNU Lesser General Public License, MIT License, Eclipse Public License and Mozilla Public License . </P> <P> The proliferation of open - source licenses is a negative aspect of the open - source movement because it is often difficult to understand the legal implications of the differences between licenses . With more than 180,000 open - source projects available and more than 1400 unique licenses, the complexity of deciding how to manage open - source use within "closed - source" commercial enterprises has dramatically increased . Some are home - grown, while others are modeled after mainstream FOSS licenses such as Berkeley Software Distribution ("BSD"), Apache, MIT - style (Massachusetts Institute of Technology), or GNU General Public License ("GPL"). In view of this, open - source practitioners are starting to use classification schemes in which FOSS licenses are grouped (typically based on the existence and obligations imposed by the copyleft provision; the strength of the copyleft provision). </P>

Which of the following is not an example of open-source software