public static function onSkinPreloadExistence( array &$titles, Skin $skin ) {
$context = MobileContext::singleton();
if ( $context->shouldDisplayMobileView() && !$context->isBlacklistedPage() ) {
$skin->getOutput()->setTarget( 'mobile' );
}
return true;
}The hook is documented as "Supply titles that should be added to link existence cache before the page is rendered". MobileFrontend is abusing it to do something totally different.