You can examine the site target in the Maven pom.xml file included at the top level of the HBase source for details on the process of building the website and documentation. The Reference Guide is built twice, once as a single-page output and once with one HTML file per chapter. The single-page output is located in target/docbkx/book.html, while the multi-page output's index page is at target/docbkx/book/book.html. Each of these outputs has its own images/ and css/ directories, which are created at build time.