According to the cyclonedx specification, the default content type is "text/plain" (https://github.com/CycloneDX/specification/blob/1.5/schema/bom-1.5.schema.json#L672). This seems reasonable as "text/plain" is a common mime type (https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types). The cyclonedx core java class LicenseLoader sets the content type field to "plain/text" (https://github.com/CycloneDX/cyclonedx-core-java/blob/master/src/main/java/org/cyclonedx/util/LicenseResolver.java#L200) which is not a MIME type.