Special:LanguageStats is a special page provided by the Translate extension. When it calls CentralNotice, this second extension expects a non existing banner.
**Reproduce step**
https://test.wikipedia.org/w/index.php?title=Special%3ALanguageStats&x=D&language=en&suppresscomplete=1
**Stacktrace**
[PEwpAADkAAjFyvIMAAABG] /wiki/Special:LanguageStats BannerExistenceException from line 348 of /srv/mediawiki/php-1.29.0-wmf.11/extensions/CentralNotice/includes/Banner.php: No banner exists where tmp_name = WikiCon. Could not load.
#0 /srv/mediawiki/php-1.29.0-wmf.11/extensions/CentralNotice/includes/Banner.php(176): Banner->populateBasicData()
#1 /srv/mediawiki/php-1.29.0-wmf.11/extensions/CentralNotice/includes/Banner.php(827): Banner->getName()
#2 /srv/mediawiki/php-1.29.0-wmf.11/extensions/CentralNotice/includes/Banner.php(814): Banner->getMessageFieldsCacheKey()
#3 /srv/mediawiki/php-1.29.0-wmf.11/extensions/CentralNotice/includes/BannerMessageGroup.php(69): Banner->getMessageFieldsFromCache()
#4 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/messagegroups/MessageGroupOld.php(282): BannerMessageGroup->getDefinitions()
#5 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/utils/MessageGroupStats.php(401): MessageGroupOld->initCollection(string)
#6 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/utils/MessageGroupStats.php(362): MessageGroupStats::calculateGroup(BannerMessageGroup, string)
#7 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/utils/MessageGroupStats.php(250): MessageGroupStats::forItemInternal(array, BannerMessageGroup, string)
#8 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/utils/MessageGroupStats.php(107): MessageGroupStats::forLanguageInternal(string)
#9 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/specials/SpecialLanguageStats.php(369): MessageGroupStats::forLanguage(string)
#10 /srv/mediawiki/php-1.29.0-wmf.11/extensions/Translate/specials/SpecialLanguageStats.php(156): SpecialLanguageStats->getTable()
#11 /srv/mediawiki/php-1.29.0-wmf.11/includes/specialpage/SpecialPage.php(522): SpecialLanguageStats->execute(NULL)
#12 /srv/mediawiki/php-1.29.0-wmf.11/includes/specialpage/SpecialPageFactory.php(577): SpecialPage->run(NULL)
#13 /srv/mediawiki/php-1.29.0-wmf.11/includes/MediaWiki.php(285): SpecialPageFactory::executePath(Title, RequestContext)
#14 /srv/mediawiki/php-1.29.0-wmf.11/includes/MediaWiki.php(860): MediaWiki->performRequest()
#15 /srv/mediawiki/php-1.29.0-wmf.11/includes/MediaWiki.php(521): MediaWiki->main()
#16 /srv/mediawiki/php-1.29.0-wmf.11/index.php(43): MediaWiki->run()
#17 /srv/mediawiki/w/index.php(3): include(string)
#18 {main}