Binary package “docbook-xsl” in ubuntu focal

stylesheets for processing DocBook XML to various output formats

 These are modular XSL stylesheets for processing documents composed
 with the DocBook XML DTD and its derivatives ("Simplified" DocBook
 XML, JRefEntry DTD, etc.).
 .
 The stylesheets provide XSLT transformations for (X)HTML, WordML, HTML Help,
 JavaHelp, Man page (nroff), Website, Eclipse Platform Help file and XSL
 Formatting Object (XSL-FO) output. The latter can be further processed to
 a number of print formats using FOP or TeX-based tools.
 .
 The stylesheets are modular in the sense that you can extend and, to some
 extent, customize them. The documentation is included in a separate package.