Both clientConvertersCustomizer and serverConvertersCustomizer are ordered with lowest precedence. This prevents a user's customizer from overriding the default customisation as the user's customizer cannot be guaranteed to go last. Ordering them at 0 would allow a user's customizer to go before or after the default customizers.
Ordering of message converter beans is also significant as they're applied in order by the default customizers. We could order the auto-configured message converter beans at 0 to ease overriding those as well.
Comment From: namest504
I'd like to contribute to this issue.