Once XML files have been validated, run make html-en. Creating HTML files is important to have an idea about what users will see. You will probably notice some improvements to be made on your XML file.

You can make an HTML draft (when the folder xml/en has been created during validation) for a single source xml file, by running, for instance, the command make xml/en/concepts/brushes.draft. This create the brushes-draft.html for the brushes.xml file. But images are not embedded in draft files.

You can also use yelp and run yelp file :///your-file.xml.