Available from version 1.32.0 (Gerrit change 456389)
Allows modifying the query used by Special:AncientPages.
Define function:
public static function onAncientPagesQuery( &$tables, &$conds, &$joinConds ) { ... }
Attach hook: In extension.json:
	"Hooks": {
		"AncientPagesQuery": "MediaWiki\\Extension\\MyExtension\\Hooks::onAncientPagesQuery"
Called from: File(s): specials/SpecialAncientpages.php
Function(s): getQueryInfo
Interface: AncientPagesQueryHook.php

For more information about attaching hooks, see Manual:Hooks .
For examples of extensions using this hook, see Category:AncientPagesQuery extensions.