Open source technology, by its very definition, is technology that anyone can use, modify, and share without paying any royalties or fees. This concept is different from closed source technology, which is proprietary and may or may not incur a fee for its usage--case in point: Adobe Acrobat Reader DC vs. Adobe Creative Cloud--but usually restricts the user from modifying or redistributing the technology (or accessing its source code) without legal permission from its owner. By virtue of its open and free nature, open source software spans economies, continents, languages, and cultures. For the nonprofit community, this reinforces a sense of unity and commitment to an ethos of devotion to the greater good.
To preserve this unity and ethos, several license standards were developed and are currently used in the open source community. The individual licenses may differ slightly from one another, but most will typically govern how packages like Red Hat, Ubuntu, Debian, other Linux distributions, Android, Apache, Mozilla Firefox, GNU C/C++ Compiler, and others can be used, modified, and distributed. For example, licenses often require modifications of an open source software or operating system package to be licensed with the same license as the original software they are derived from; this illustrates a concept colloquially known in the open source community as "copyleft."
Here are some of the most commonly used open source licenses:
To learn more about open source licenses and the overall mission of the Open Source Definition (OSD), visit the Open Source Initiative at https://opensource.org/.