The content of fabric8-project-bom-camel-spring-boot is derived from a combination of the spring-boot-dependencies BOM and the camel-spring-boot-dependencies BOM. Unfortunately, cxf-rt-rs-extension-providers is not present in either of those, hence it's missing in the combined BOM.

Add the missing dependency to camel-spring-boot-dependencies and it'll get picked up when the combined BOM is generated