feat: plugin license

contributing.md

@@ -152,6 +152,7 @@ If you want your plugin to be displayed in the readme and possibly inside the us
   - Understanding JS types and reading TypeScript definitions
   - Semantic versioning (for versioning your plugin in the correct format)
 - Basic knowledge of userscripts (start on the [GreaseSpot wiki](https://wiki.greasespot.net/Greasemonkey_Manual))
+- Reading the file [`license-for-plugins.txt`](./license-for-plugins.txt) to understand the licensing conditions for plugins
   
 **Helpful knowledge:**
 - TypeScript (for type safety and better autocomplete)

license-for-plugins.txt

@@ -0,0 +1,25 @@
+For the purpose of creating plugins, anyone is hereby allowed to freely copy,
+modify, embed, redistribute, sublicense and sell copies of the source code of
+all `.d.ts` and `.json` files in the BetterYTM project.
+
+Furthermore, you may include the source code of this project in yours, as long
+as only the above mentioned files are included in the final build.
+All files not mentioned above are licensed under the AGPL-3.0-only license.
+
+Lastly, you are to make the source code of your plugin available to anyone who
+requests it, and you are to provide a link to said source code in the plugin
+definition object needed for registering the plugin at runtime.
+
+Failure to comply with these terms will result in your plugin not being
+endorsed by the BetterYTM project or even legal action if necessary.
+
+Use is granted under the condition that the original author and the BetterYTM
+project is credited in the source code of the plugin.
+
+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 NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS 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.