The "master document" (selected by :confval:`master_doc`) is the "root" of
the TOC tree hierarchy. It can be used as the documentation's main page, or
as a "full table of contents" if you don't give a ``maxdepth`` option.
+Sphinx reserves some document names for its own use; you should not try to
+create documents with these names -- it will cause problems.
+The special document names (and pages generated for them) are:
+* ``genindex``, ``modindex``, ``search``
+ These are used for the general index, the module index, and the search page,
+ The general index is populated with entries from modules, all index-generating
+ :ref:`description units <desc-units>`, and from :dir:`index` directives.
+ The module index contains one entry per :dir:`module` directive.
+ The search page contains a form that uses the generated JSON search index and
+* every name beginning with ``_``
+ Though only few such names are currently used by Sphinx, you should not create
+ documents or document-containing directories with such names. (Using ``_`` as
+ a prefix for a custom template directory is fine.)
+``index`` is a special name, too, if the :confval:`html_index` config value is