Download
You can show a download button. If the file is not available the button will be marked with "Offline". You should prefix local downloads with a slash. These will be linked to your public directory. You can also use external downloads from other sources.
:download[Herunterladen]{src="/test.zip"}
 
:download[Herunterladen]{src="/test.jpg"}
    This download links to a file test.zip in the public folder.
    Unfortunately, the file is not available.
  
This download links to a file test.jpg in the public folder.
If your hyperbook uses the basePath property, the basePath will automatically be prepended.