A FreeSurfer developer works on the FreeSurfer software suite, which is widely used in neuroscience for brain imaging analysis. Their tasks involve the creation, testing, and maintenance of algorithms for processing and visualizing MRI data. They handle the development of tools for the reconstruction of the brain's cortical surface from structural MRI data, the segmentation of subcortical structures, and the integration of functional MRI data. They also work on improving the accuracy, efficiency, and usability of the software. Furthermore, they provide technical support to users, and collaborate with researchers to implement new features or improvements.