Yup, it's handled elsewhere, as the StoragefileItem needs to be retrieved from Nx repo to get it's timestamp. See here
https://github.com/sonatype/nexus-oss/blob/6c6c45b765682712b95f2b2a8ed1b286d6bff393/plugins/basic/nexus-content-plugin/src/main/java/org/sonatype/nexus/content/internal/ContentServlet.java#L436