A FusionForge developer primarily works on the FusionForge software, an open-source collaborative development platform. They are responsible for creating, maintaining, and improving the software's features that facilitate collaboration within software development teams. This includes project management, version control, bug tracking, and more. They also work on ensuring the software's security and stability. Additionally, they may collaborate with other developers to integrate FusionForge with other tools and software, and provide support to users. Their work is crucial in providing an efficient environment for developers to collaborate, manage, and track their software development projects.