A Freemind developer works on the Freemind open-source software, a mind-mapping tool that facilitates organizing and brainstorming ideas visually. Key responsibilities include coding, debugging, and updating the software to improve its functionality, user-friendliness, and stability. They also address user feedback or reported issues, ensuring the software runs smoothly on different operating systems. In addition, Freemind developers collaborate with other team members to design new features, enhance the software's overall performance, and maintain its documentation. They typically work with Java programming language, as Freemind is written in Java. They must stay updated on new technologies to ensure the software remains competitive.