Hi Andrius, asciidoc-base is as a base package and meant to be minimal especially meant to be used for manpage. The whole xsltproc thing has a lot of dependencies that are not always suitable in build environments for example. I wouldn't recommend using a2x for generating manpages. This relies on the whole xslt machinery. You can just use the asciidoc command-line. Example:
asciidoc -d manpage ~/Downloads/doc_a2x.1.txt Joseph