During April 2025, Benjamin Pérez-Crespo developed the Observable: Deferred Observer Removal feature for the Babylon.js repository, focusing on enhancing event handling reliability in complex scenes. He introduced an optional defer parameter to observer removal, updating both Observer.remove and internal _remove logic within Observable.add. This approach, implemented in TypeScript, addressed the issue of callback skipping during observer iteration, thereby improving the robustness of the API. Benjamin’s work demonstrated a strong grasp of API design and core development, delivering a targeted solution that increased runtime safety for event dispatching without introducing regressions, and reflecting careful integration within a large, actively maintained codebase.