The docbook2mdoc utility is a converter from DocBook V4.x and v5.x XML into mdoc. Unlike most DocBook utilities, it's a standalone ISC-licensed ISO C utility that should compile on any modern UNIX system. The only requirement is libexpat (for parsing XML), which is installed by default on most systems.
docbook2mdoc is experimental: it still has many missing elements. However, it works with the DocBook reference examples and documents found in the wild. Contact Kristaps with questions or missing nodes; or better yet, download the source and add new elements yourself as described in the README.
New in version 0.0.9...
Now supports most tags as found in the OpenGL DocBook corpus.
The main missing elements are
although a few others (
<footnote> et al.) are in there too.
The DocBook is also malformed in some areas—improper parenting.