Available from version 1.19.0 (r94435)
allows to set conditions for query when links to certain title
Define function:
public static function onBacklinkCacheGetConditions( $table, $title, &$conditions ) { ... }
Attach hook: In extension.json:
	"Hooks": {
		"BacklinkCacheGetConditions": "MyExtensionHooks::onBacklinkCacheGetConditions"
Called from: File(s): cache/BacklinkCache.php
Interface: BacklinkCacheGetConditionsHook.php

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