Hi all another trick ! : open page https://www.mediawiki.org/wiki/Category:MediaWiki_version_templates and see the ugly (i'm sorry about the term) html pending string displayed to the user :
<td title="MediaWiki ? is unknown version" style="border-color: #c8ccd1; border-width: 5px; border-style: solid; text-align: center; padding: .1em .3em;"> ?