sgml-base binary package in Ubuntu Xenial amd64

 This package creates the SGML infrastructure directories and provides
 SGML catalog file support in compliance with the current Debian SGML
 Policy draft:
 .
   * infrastructure directories:
      - /etc/sgml
      - /usr/share/sgml/{declaration,dtd,entities,misc,stylesheet}
      - /usr/share/local/sgml/{declaration,dtd,entities,misc,stylesheet}
 .
   * update-catalog(8): tool for maintaining the root SGML catalog
     file and the package SGML catalog files in the '/etc/sgml' directory

Source package