Metadata specification is documented here: WritingSpecification#Metadataclients.xml
The 'client tag' chart is missing some elements that are described on the Authentication page; it would be handy to have a link (in both directions!)
On the Authentication page, it might be handy to point out that the 'uuid' should correspond to the value of the 'name' parameter in the client's bcfg2.conf.
Also, I'd rather the 'client tag' chart be documented on the Metadata page so I can find it easily through the index without having to think (ouchy). The groups chart is also split between the WritingSpecification and Metadata pages. In fact, the Metadata plugin is the only one whose specification's main documentation is in the WritingSpecification page. (And if the Xinclude stuff on the WritingSpec? page only applies to Metadata, it should be moved along with the Metadata docs.)
