During December 2024, Mathieu Marchand enhanced network configuration flexibility in the major/cloud-init repository by introducing manual subnet type support. He updated the network schema to allow manually configured interfaces, addressing deployment needs in custom networking environments. Mathieu implemented comprehensive unit tests in Python to verify correct handling of the new subnet type, focusing on schema validation and reducing the risk of misconfiguration. His work included detailed documentation in RST, ensuring clarity for future maintainers. By extending the allowed subnet types and improving test coverage, Mathieu delivered targeted, test-backed changes that increased deployment reliability for customers with specialized networking requirements.