Install xmlroff by entering the following commands in the terminal:
sudo apt update sudo apt install xmlroff
Description:
XSL formatter mainly for DocBook
xmlroff is a fast, free, high-quality, multi-platform XSL formatter that aims to excel at DocBook formatting and that integrates easily with other programs and with scripting languages.
Homepage: http://xmlroff.org
Version: 0.6.2-1.3build1
Section: universe/text