The pages on this website are written in markdown syntax and stored in SVN at https://svn.apache.org/repos/asf/incubator/odf/site
Via integration with the Apache CMS, it is possible to edit, stage and publish website updates from the command line, or by using a web-based interface.
Detailed information can be found in the How to edit the ODF website page.
Information on deeper website development is found on the Website Development page.
Information can be found on this blog.