'CanonicalNamespaces': For extensions adding their own namespaces or altering
the defaults.
+Note that if you need to specify namespace protection or content model for
+a namespace that is added in a CanonicalNamespaces hook handler, you
+should do so by altering $wgNamespaceProtection and
+$wgNamespaceContentModels outside the handler, in top-level scope. The
+point at which the CanonicalNamespaces hook fires is too late for altering
+these variables. This applies even if the namespace addition is
+conditional; it is permissible to declare a content model and protection
+for a namespace and then decline to actually register it.
&$namespaces: Array of namespace numbers with corresponding canonical names
'CategoryAfterPageAdded': After a page is added to a category.