SpringBoot Default MIME mappings are not loaded unless additional mappings are configured

Spring Boot version: 3.3.0-RC1

In my TomcatEmbeddedContext none of the default MIME mappings are available.

This problem exists since commit 038ea2cb9a5ca22c61355e025c96587bc7890685. I commented my findings on this commit: https://github.com/spring-projects/spring-boot/commit/038ea2cb9a5ca22c61355e025c96587bc7890685#diff-68bf6ea3051d79bb9131d951d76a3a2e1e4dbe117a7ea545f28e59f68e7acc82R98

If I add

server.mime-mappings:
    "js": "text/javascript"

to my application.yml, all default mappings are loaded correctly.