There are open bug reports and the package requires some attention to fix
them. Apart from that there is not much activity around this package. Upstream is inactive and distributions share patches to fix the known bugs.
The package description is: Converts DocBook/XML documents into man pages and TeXinfo
The main tools are:
* docbook2x-man: converts a DocBook/XML refentry into a manual page,
with table support
* docbook2x-texi: converts a DocBook/XML refentry into an info page,
most usable for Emacs users