sgml2x binary package in Ubuntu Focal amd64

 sgml2x allows to easily format SGML and XML documents using DSSSL
 stylesheets, and provides the following features:
  * Multiple possible stylesheets per document class
  * Easy specification of style-sheets using sort aliases
  * Easy integration of new stylesheets by adding a simple new
  definition file in a configuration directory
  * The caller can specify a PATH-like list of configuration
  directories, defaulting to one system-wide, one per-user, and
  one per-project configuration directory
  * Automatic selection of a default stylesheet to be used
 .
 It will currently be most useful with one of the suggested sets of
 DSSSL stylesheets for DocBook.

Source package