Investigate CXF default content-type for responses and how to set a different default

Currently, the default seems to be when you do not specify an @Produces or ?_type=xxx

Content-Type application/xhtml+xml;charset=UTF-8

First of all, we need to decide whether application/xml;charset=UTF-8 wouldn't be a better default, and secondly, we need to investigate and document how the default content-type can be configured in cxf