HR-XSL comes bundled with a script and the recommended third-party libraries for XSLT and DocBook processing. Therefore, HR-XSL requires only three additional packages to get started:

Strictly speaking, however, HR-XSL requires none of the above. An XSLT 2.0-compatible processor is all that is needed to convert an HR-XML Resume into DocBook format. You could then write some basic XSLT code to convert the DocBook file into any format you wish. In other words, the bundled script and libraries are certainly not required to use the HR-XSL stylesheets.

Realistically, though, HR-XSL has only been tested with the XSLT processors and DocBook XSL stylesheets included in the lib directory of the distribution. In fact, Saxon-B is probably the only open-source XSLT processor capable of handling the HR-XSL stylesheets properly. It is therefore recommended that you use only the bundled libraries (unless you have some compelling reason not to).