Kubeval is a command-line tool that plays a crucial role in validating Kubernetes manifests and YAML files using the Kubernetes API schema, helping users spot and rectify misconfigurations that could potentially introduce flaws into a cluster. The article highlights how to install Kubeval on Linux, validate files using it, and convert results into JSON or TAP formats for better analysis. It also introduces ValidKube, a web tool that cleans up YAML files to ensure they are clutter-free, thereby enhancing Kubernetes security and simplifying cluster management tasks. Additionally, the text mentions Earthly, a tool that complements Kubeval by providing reproducible builds to strengthen CI pipelines, while emphasizing the importance of maintaining security as a priority in Kubernetes environments.