If you want to manipulate the resulting DocBook, you can create groovy scripts for certain elements, e.g. to replace the info section of an article element write a script named article.groovy. When executing herold use the command line argument --docbook-script-path to point to the directory which contains your script. Here is an example:

herold --in=Article.html --out=Article.xml --docbook-script-path=./scripts/docbook

The groovy script article.groovy

import javax.xml.xpath.*
import org.dbdoclet.trafo.tag.docbook.DocBookTagFactory

println "Customizing element article..."

def xpath = XPathFactory.newInstance().newXPath()

def nodes = xpath.evaluate( './info', node, XPathConstants.NODESET )

nodes.each { 
  node.removeChild(it);
}

DocBookTagFactory dbf = new DocBookTagFactory()
node.insertChild(0, dbf.createInfo().appendChild(dbf.createTitle("Customized title")))