message key to use in the name column,
$context: IContextSource object
+'SpecialTrackingCategories::preprocess': Called after LinkBatch on Special:TrackingCategories
+$specialPage: The SpecialTrackingCategories object
+$trackingCategories: Array of data from Special:TrackingCategories with msg and cats
+
+'SpecialTrackingCategories::generateCatLink': Called for each cat link on Special:TrackingCategories
+$specialPage: The SpecialTrackingCategories object
+$catTitle: The Title object of the linked category
+&$html: The Result html
+
'SpecialUploadComplete': Called after successfully uploading a file from
Special:Upload.
&$form: The SpecialUpload object