Shaun McCance has announced the release of gnome-doc-utils 0.17.2:

I've just released gnome-doc-utils 0.17.2, which includes
all the build magic for Mallard documents.  Using it is
similar to using the DocBook build magic, except:

1) You don't use DOC_MODULE.

2) Set DOC_ID to a system-unique identifier for the document.
This will determine where your document is installed.  For
instance, if "DOC_ID=empathy", then your document will go
into "/usr/share/gnome/help/empathy".

3) Set DOC_PAGES to the list of page files in your document.
Just as with DOC_ENTITIES or DOC_INCLUDES, do not include the
leading "C/".

exactly as for DocBook documents.

We need to work on xml2po some.  Its default operation isn't
producing the best results for Mallard documents.

Those of you working on Mallard documents, please hammer on
this and let me know if you have any problems.