// understood.
new com.google.gdata.data.Feed().declareExtensions(extProfile);
// The default metadata registry contains the basic feed plus the
// version transforms for atom and atompub.
this.metadataRegistry = new MetadataRegistry();
Feed.registerMetadata(metadataRegistry);
AtomVersionTransforms.addTransforms(metadataRegistry);
AtompubVersionTransforms.addTransforms(metadataRegistry);
}