underscore) magic words. Called by MagicWord.
&$doubleUnderscoreIDs: array of strings
+'GetExtendedMetadata': Get extended file metadata for the API
+&$combinedMeta: Array of the form: 'MetadataPropName' => array(
+'value' => prop value, 'source' => 'name of hook' ).
+$file: File object of file in question
+$context: RequestContext (including language to use)
+&$maxCacheTime: how long the results can be cached
+
'GetFullURL': Modify fully-qualified URLs used in redirects/export/offsite data.
$title: Title object of page
$url: string value as output (out parameter, can modify)
$userText: User name of the current user
&$items: Array of user tool links as HTML fragments
+'ValidateExtendedMetadataCache': Called to validate the cached metadata in
+FormatMetadata::getExtendedMeta (return false means cache will be
+invalidated and GetExtendedMetadata hook called again).
+$timestamp: The timestamp metadata was generated
+$file: The file the metadata is for
+
'WantedPages::getQueryInfo': Called in WantedPagesPage::getQueryInfo(), can be
used to alter the SQL query which gets the list of wanted pages.
&$wantedPages: WantedPagesPage object