An LLDB developer is responsible for designing, developing, and optimizing the LLDB debugger, a part of the LLVM open-source project. They write and debug code, fix bugs, and improve the tool's functionality. Their work involves understanding complex systems, programming languages, and architectures. They also collaborate with other developers to integrate LLDB with different IDEs and tools. Additionally, they need to keep abreast of the latest advancements in compiler technology and programming languages. A strong background in computer science and experience in C++ and Python programming are typically required for this role.