An Apache module development developer designs, codes, and tests modules for the Apache HTTP Server. They use programming languages like C and Perl to create modules that extend the functionality of the Apache server. This includes tasks like handling specific types of HTTP requests, modifying server behavior, or adding new features. They also debug and fix issues in existing modules, as well as optimize their performance. They work closely with other developers and stakeholders to understand their needs and ensure the module meets those requirements. Additionally, they document their work and may provide user support.