Install docbook-simple by entering the following commands in the terminal:
sudo apt update sudo apt install docbook-simple
Description:
simplified DocBook XML Doctype and css stylesheets
The Simplified DocBook is a small subset of the DocBook DTD. It has ~100 elements, rather than the >350 elements in the full DocBook DTD. A good choice when full DocBook is overkill.
Homepage: http://www.oasis-open.org/docbook/xml/simple/
Version: 1.1-4.2
Section: universe/text