Open Source Copyleft License (OSCL) v1.0

Open Source Copyleft License (OSCL) Version 1.0, 21 February 2026 Copyright © 2026 Timofey Zakharchuk Preamble The Open Source Copyleft License (OSCL) is a free, copyleft license for software and other kinds of works. Most software licenses are designed to restrict your freedom to share and modify works. By contrast, the OSCL is intended to guarantee your freedom to use, study, modify, reproduce, prepare derivative works, and distribute all versions of a program—ensuring that it remains free software for all its users. You can apply it to your programs, too. When we speak of free software, we are referring to freedom, not price. The OSCL is designed to ensure that you have the freedom to distribute copies of free software (whether gratis or for a fee), to receive source code or obtain it if you want it, to change the software or use pieces of it in new free programs, and to know that you can do these things. To protect your rights, the OSCL requires that Modifications and Derivative Works remain under the same license. This ensures that recipients of your software enjoy the same freedoms you received. If you distribute copies of a program, you must also provide access to the Source Form, and you must show recipients these terms so they understand their rights. Developers who use the OSCL protect your rights with two steps: (1) assert copyright on the Software, and (2) offer you this License as the Licensor, granting legal permission to copy, distribute, and modify it. For the protection of both users and Licensors, the OSCL clearly explains that there is no warranty for this free software. It also requires that modified versions be marked as changed, so that problems are not erroneously attributed to Licensors or Contributors of previous versions. Some devices are designed to deny users the ability to install or run modified versions of the software inside them, even though the manufacturer can do so. This practice is incompatible with the aim of protecting users’ freedom to change the software. The OSCL prohibits such restrictions, ensuring that recipients can run modified versions of the Software. Finally, every program is threatened by software patents. To prevent patents from being used to make free software proprietary, the OSCL requires that Contributors and Distributors grant patent licenses covering their Contributions. This ensures that patents cannot be used to render the Software non-free. The precise terms and conditions for copying, distribution, and modification follow. Definitions: “Author” means the original creator of the Software. “Licensor” means the individual or legal entity that has the right to license the Software under this License, including the Author or any assignee or successor. “Contributor” means any person who submits code, documentation, or other material that is incorporated into the Software by the Licensor or project maintainers. “Software” means the code, assets, and other files that are explicitly distributed under this License by the Licensor. “Modification” means any change to the Software, including additions, deletions, or alterations of existing material. “Derivative Work” means any work that incorporates or modifies the Software such that the modified portions form a single program with the Software. Mere linking to the Software’s public interfaces, without modifying the Software, does not create a Derivative Work. “Distribution” means making the Software or a Derivative Work available to any third party in any form, including source code, object code, or executable form. “Source Form” means the preferred form of the work for making Modifications. 1. Credit Redistribution or Distribution of the Software or any Derivative Work must preserve all existing copyright notices, this License text, and any attribution notices identifying the Author or Licensor already present in the source files. No additional or subjective forms of attribution are required. 2. Copyright Notice The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. 3. No Endorsement Neither the name of the Licensor nor the names of Contributors may be used to endorse or promote products derived from this Software without specific prior written permission. 4. Patent Grant Each Contributor and Distributor of the Software hereby grants to all recipients a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated below) patent license under any patent claims they own or control that are necessarily infringed by their Contribution or Distribution of the Software, to make, use, sell, offer for sale, import, run, modify, and distribute the Software and any Derivative Works, solely to the extent such actions are permitted by this License. This patent license terminates automatically if you initiate patent litigation (including a cross-claim or counterclaim) alleging that the Software or a Contribution incorporated within the Software directly or indirectly infringes any patent. You may distribute Modifications in the form of patches to the original Software, provided that the recipient can apply them to produce a modified work under the terms of this License. 5. Contributor License Grant Each Contributor grants a royalty-free, perpetual, worldwide license under their copyright and any patent claims they own or control that are necessarily infringed by their Contributions, but only to the extent of the changes they contributed. This grant does not apply to any code or patents not contributed to the Software. 6. Copyleft: No Surrender of Others’ Freedom a. Any Modification of the Software must be licensed, in its entirety and in Source Form, under this License, version 1.0 or, at the recipient’s option, any later version published by the Licensor and approved by the Open Source Initiative. b. Any Derivative Work, as defined above, must be licensed under this License. c. A work that merely links to the Software, uses its public interfaces, or depends on it at runtime, without modifying it, is not a Derivative Work and may be licensed under any terms. d. You may distribute object code or executable forms of a Derivative Work provided that the complete corresponding Source Form is made available under the terms of this License. e. Mere aggregation of the Software on a storage or distribution medium with separate and independent works that are not combined into a unified work does not create a Derivative Work. 7. Stewardship of Future Versions The Licensor may designate a steward organization to publish future versions of this License. If the Licensor is no longer maintaining the License, the project community may designate a steward organization to publish future versions. 8. Distribution Distribution of the Software in object or executable form must be accompanied by the complete corresponding Source Form, or a written offer valid for at least three years to provide the Source Form at no more than the cost of physically performing source distribution. The Source Form must be made available via a publicly accessible network server (e.g., Internet download) or equivalent well-publicized means. Distribution must not impose technical restrictions that prevent recipients from running modified versions of the Software. 9. Compatibility OSCL‑licensed code may also be distributed under the terms of the GNU General Public License (GPL). This constitutes dual licensing: recipients may choose to comply with OSCL or GPL. OSCL‑licensed code must remain under OSCL, even when distributed under GPL terms. Code originally licensed under the GPL may not be relicensed under OSCL. This compatibility is one‑way: OSCL to GPL, but not GPL to OSCL. 10. Disclaimer of Warranty and Limitation of Liability TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION. IN NO EVENT SHALL THE LICENSOR OR CONTRIBUTORS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. If applicable law does not allow the full exclusion of liability, this disclaimer shall be enforced to the maximum extent permitted. This License does not discriminate against any person or group, nor restrict the use of the Software in any field of endeavor. The rights granted under this License apply to all recipients of the Software, without requiring a separate license agreement. End of License. How to apply OSCL to your work To apply OSCL to your work, attach the following notice to each files Copyright © [year] [Name of Copyright holder] This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Open Source Copyleft License for more details. You should have received a copy of the Open Source Copyleft License along with this program. If not, see <https://areponian.github.io/oscl.html>.