YAML (Yet Another Markup Language) is a human-readable data format used for writing configuration files in many DevOps tools, including Ansible, Kubernetes, and Docker Compose. It is favored for its simplicity and clarity, allowing teams to define infrastructure, application settings, and deployments declaratively. YAML files are easy to version control, review, and reuse, making them ideal for configuration management. Unlike binary files (.exe, .mp4) or media files (.jpg), YAML is structured text that represents data hierarchically, aligning perfectly with the goals of reproducibility and transparency in CD pipelines.