copylefteisen

Copyleft is a general method for making a program, or other work, free, and requiring all modified and extended versions of the program to be free as well. The term "copyleft" is a play on the term "copyright". Copyleft is a legal mechanism: a copyright license that requires derived works to be licensed under identical terms. Copyleft is used to ensure that users have the freedom to use, study, share, and modify the software. The most well-known copyleft license is the GNU General Public License (GPL), created by the Free Software Foundation. The GPL is a copyleft license that requires any derivative work to be distributed under the same terms as the original work. This ensures that the software remains free and open-source. Copyleft is often contrasted with permissive licenses, which allow the software to be used in proprietary software without requiring the derivative work to be open-source. Copyleft licenses are designed to protect the freedom of users and developers, ensuring that the software remains open and accessible to all.