An Augeas developer works with the Augeas tool, a configuration editing utility and Puppet resource. They write and maintain lenses, which are modules that define how Augeas parses and serializes files. Developers use Augeas to manage configuration files programmatically, ensuring consistency and correctness across complex systems. They also troubleshoot issues, create new features, and improve the tool's efficiency and usability. Augeas developers need strong knowledge in system administration, configuration management, and programming. They also need to understand the structure and syntax of various configuration files to create effective lenses.