Has someone recently changed something with the <source lang="php"> extension, style ? Layout is broken
filed as *Bug 35968* https://bugzilla.wikimedia.org/show_bug.cgi?id=35968 -syntaxhighlight layout broken on MediaWiki.org : rendered as i) an empty line with borders before and ii) missing border box and background around the code (edit https://bugzilla.wikimedia.org/process_bug.cgi#)