.css file present will be used. $langCodes = array_merge( [ $wgContLang->getCode() ], $wgContLang->getFallbackLanguages() ); foreach ( $langCodes as $lang ) { $langStyleFile = 'ext.cite.style.' . $lang . '.css'; $localPath = $this->getLocalPath( $langStyleFile ); if ( file_exists( $localPath ) ) { $this->styles[] = $langStyleFile; break; } } } }