How is this supposed to work and pls show me where this is documented.

This is an XB extension to plain MC bean element, search for "urn:jboss:pojo2osgi" to find the actual metadata class.

In MC's BeanMetaData we have a notion of related classes; e.g. used with AOP, BeanFactory, ...

With OSGi we could simply reuse this related classes metadata to hold the explicit exposed types.

See how CLASSES const is created for MC beans in that MDR factory -- it reuses this related classes info.

So, instead of all that xml details, we can simply hide this behind <exposed-type> element.