It can be accessed by clicking the Sitemap1) link in the global navigation, or called by adding
&do=index at the end of your wiki URL. To view a specific branch of your wiki, you can call
Be aware that it reveals namespaces (but not pages) that may be protected by the ACL. There is a sneaky index option you can set in your configuration file to enable protected namespace hiding in the Index. This option is not turned on by default since this will hide accessible pages that are children of an otherwise protected namespace.