such as Special:MyPage and Special:MyTalk.
&$redirectParams: An array of parameters preserved by redirecting special pages.
+'RejectParserCacheValue': Return false to reject an otherwise usable
+cached value from the Parser cache.
+$parserOutput: ParserOutput value.
+$wikiPage: WikiPage object.
+$parserOptions: ParserOptions object.
+
'RequestContextCreateSkin': Called when RequestContext::getSkin creates a skin
instance. Can be used by an extension override what skin is used in certain
contexts.