Worked on core reliability improvements and developer experience across envoyproxy/gateway and cert-manager/website repositories. Addressed TLS certificate reference handling in ListenerSet validation by updating Go-based backend logic to accept unresolvable certificates per Gateway API specifications, distinguishing between InvalidCertificateRef and RefNotPermitted cases. Enhanced unit tests and YAML fixtures to ensure regression safety and accurate API conformance. Improved documentation in Markdown for cert-manager/website, adding detailed examples and clarifying ACME HTTP-01 challenge patterns to reduce user confusion. Focused on API development and Kubernetes integration, these changes reduced integration friction and provided clearer guidance for users adopting ACME challenges in production environments.