During December 2025, Oandregal focused on improving the robustness of theme JSON resolution in WordPress core, working across both the peterwilsoncc/wordpress-develop and WordPress/WordPress repositories. By introducing WP_Post instance validation within the Theme_JSON_Resolver, Oandregal addressed a recurring source of runtime errors, enhancing reliability for theme processing in both core and forks. The solution involved careful PHP development and adherence to WordPress coding standards, including a core version bump and resolution of issue #64434. This backend engineering work reduced support overhead and improved user experience by ensuring safer query handling and more stable theme JSON processing across deployments.