A Bitbake developer is responsible for creating and managing software recipes using the Bitbake build engine in the Yocto Project, an open-source collaboration project that provides templates, tools, and methods to help create custom Linux-based systems for embedded products. They handle tasks like configuring and building Linux kernel, creating root file system, and integrating and debugging software packages. They are involved in cross-compiling, packaging, and creating and maintaining different layers in Yocto. Their role also includes improving the build process, automation, and handling software versions for embedded systems. They also ensure system compatibility and performance optimization.