Exlusion of various things:

Exporting to html using Render Engine: CKGedit

***.pdf**
It should be possible to exclude ".pdf" downloads, but I cannot come up with the correct REGEX expression. It gets tangled up with the dw2pdf plugin, somehow. Still fussing with this.

**[ns]:blank** and the parent ns if it is empty.
so we can exclude them

Also any empty [ns]

pre in headers etc.

Start by reproducing an HTML export with the Render Engine CKGedit and the dw2pdf plugin, then inspect the existing exclusion regex handling. Verify how PDF downloads, empty [ns] entries and parent namespaces, and preformatted header content are represented; done means the requested exclusions work without interference from dw2pdf.

Written by the indexing model from the issue text.