Dreamwidth inherited from Livejournal a system for building server-side documentation about how the codebase works. However, these docs haven't been kept up to date; there is more, and much more recent, documentation on this wiki.
However, if for some reason you want to try and build some docs which describe how the LJ code worked long ago, you can try the following steps, though it may be difficult to get it to work.
These instructions are based on the ones given in the bug report.
First, you will want to install some necessary packages if you don't have them already:
sudo apt-get install docbook-xml xsltproc docbook-xsl
Symlink the docbook xsl provided by the Debian/Ubuntu package to the place where generate.pl expects to find it:
ln -s /usr/share/xml/docbook/stylesheet/docbook-xsl/ $LJHOME/doc/raw/build/ xsl-docbook
You can then generate it with:
Note: it used to be possible to download the docbook xsl using the --getxsl flag, but the repository where it was hosted has since gone offline. Fortunately, there are compatible packages in debian and ubuntu :)