Apparently it's XML-like. Example templates can be found in the gnome Anjuta shares on an Ubuntu install at /usr/share/anjuta/project/
I think I'll go back to Eclipse and gedit if it doesn't look like Anjuta has documented a decent auto-completion, project build, and syntax-highlighting template format. Others with the same question went fishing on Ubuntu forums and had no luck.
The answer might also help people trying to build automake scripts for svn repos at [https://stackoverflow.com/questions/5926366/using-anjuta-with-svn-how-to-create-the-project]