&$cookies: array of cookies name, add a value to it if you want to add a cookie
that have to vary cache options
+'GetCanonicalURL': modify fully-qualified URLs used for IRC and e-mail notifications
+$title: Title object of page
+$url: string value as output (out parameter, can modify)
+$query: query options passed to Title::getCanonicalURL()
+
'GetDefaultSortkey': Override the default sortkey for a page.
$title: Title object that we need to get a sortkey for
&$sortkey: Sortkey to use.
'InvalidateEmailComplete': Called after a user's email has been invalidated successfully
$user: user (object) whose email is being invalidated
+'IRCLineURL': When constructing the URL to use in an IRC notification.
+Callee may modify $url and $query, URL will be constructed as $url . $query
+&$url: URL to index.php
+&$query: Query string
+
'IsFileCacheable': Override the result of Article::isFileCacheable() (if true)
$article: article (object) being checked