During December 2025, Hayden Rear enhanced the spring-projects/spring-framework repository by developing a new builder API for managing HTTP message converters as an ordered list. Using Java and the Spring Framework, Hayden introduced a configureMessageConvertersList method that allows developers to add, remove, or move converters before post-processing, addressing gaps in the existing contract and reinstating the ability to append converters at the end of the list. This work improved the configurability and predictability of HTTP message conversion while maintaining backward compatibility. The implementation demonstrated a focused approach to API design and unit testing, delivering a targeted feature with clear developer benefits.