There are no specific rules for this site because it is up to scenario authors about how they license their code (and artwork etc). Normal copyright applies; by uploading the source you allow others to download it, but that doesn't give them any automatic right to claim ownership of it or redistribute it. So basically, you shouldn't use anybody else's work without obtaining their permission first. If someone uses your work and publishes it on this website without your permission, and this bothers you, then please: First, ask them to remove the scenario (or give you proper attribution for example) by posting a comment on the scenario; Second, if that has no effect, you can post to gallery@greenfoot.org or support@greenfoot.org and ask us (the administrators) to remove the scenario. You should provide at least basic evidence that someone has taken your work (for instance, provide a link to the original scenario). You can also use the "report this scenario" link on the scenario, and provide the same information.