From https://en.wikipedia.beta.wmflabs.org/w/api.php while I am logged in, but not while I am logged out:
```[XJlgAqwQBGoAAFPjDhoAAAAD] /w/api.php Wikimedia\Services\NoSuchServiceException from line 451 of /srv/mediawiki/php-master/includes/libs/services/ServiceContainer.php: No such service: MobileFrontend.Context
Backtrace:
#0 /srv/mediawiki/php-master/includes/libs/services/ServiceContainer.php(414): Wikimedia\Services\ServiceContainer->createService(string)
#1 /srv/mediawiki/php-master/extensions/MobileFrontend/includes/MobileFrontend.skin.hooks.php(182): Wikimedia\Services\ServiceContainer->getService(string)
#2 /srv/mediawiki/php-master/extensions/MobileFrontend/includes/MobileFrontend.hooks.php(178): MobileFrontendSkinHooks::prepareFooter(SkinApi, SkinApiTemplate)
#3 /srv/mediawiki/php-master/includes/Hooks.php(174): MobileFrontendHooks::onSkinTemplateOutputPageBeforeExec(SkinApi, SkinApiTemplate)
#4 /srv/mediawiki/php-master/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#5 /srv/mediawiki/php-master/includes/skins/SkinTemplate.php(481): Hooks::run(string, array)
#6 /srv/mediawiki/php-master/includes/skins/SkinTemplate.php(225): SkinTemplate->prepareQuickTemplate()
#7 /srv/mediawiki/php-master/includes/OutputPage.php(2709): SkinTemplate->outputPage()
#8 /srv/mediawiki/php-master/includes/api/ApiFormatBase.php(332): OutputPage->output()
#9 /srv/mediawiki/php-master/includes/api/ApiFormatRaw.php(85): ApiFormatBase->closePrinter()
#10 /srv/mediawiki/php-master/includes/api/ApiMain.php(1856): ApiFormatRaw->closePrinter()
#11 /srv/mediawiki/php-master/includes/api/ApiMain.php(598): ApiMain->printResult(integer)
#12 /srv/mediawiki/php-master/includes/api/ApiMain.php(538): ApiMain->handleException(Wikimedia\Services\NoSuchServiceException)
#13 /srv/mediawiki/php-master/includes/api/ApiMain.php(502): ApiMain->executeActionWithErrorHandling()
#14 /srv/mediawiki/php-master/api.php(87): ApiMain->execute()
#15 /srv/mediawiki/w/api.php(3): require(string)
#16 {main}```