As an example the documentation for 5.12 in the qtmqtt module can be taken.

If you build the documentation with a 5.12/dev based qdoc, the enum classes in the QMqtt namespace do not show up in the html documentation. For a 5.11 build of qdoc it works like a charm.

I have only tested this on Windows, but do not expect this to be a platform specific issue.