Manual:$wgUseTrackbacks

Miscellaneous settings: $wgUseTrackbacks
Allow blog style trackbacks to be attached to articles
Introduced in version:1.5.0 (r10252)
Removed in version:1.19.0 (r104051)
Allowed values:(boolean)
Default value:false

Details edit

$wgUseTrackbacks enables blog-style trackback support if set to true in LocalSettings.php . When MediaWiki receives a trackback ping, a box will show up at the bottom of the article containing a link to the originating page. The link format can be customized by editing MediaWiki:Trackbackexcerpt.

However, MediaWiki does not support sending trackback pings.

Form MediaWiki version 1.18 to 1.19 one also needed to assign relevant user groups the "trackback" right to enable this feature.