Doesn't seem to be a problem for anonymous users.
Fatal error: Uncaught Error: Class 'ContentTranslation\Action' not found in /srv/mediawiki/php-master/extensions/ContentTranslation/includes/Hooks.php:96 Stack trace: #0 /srv/mediawiki/php-master/includes/Hooks.php(174): ContentTranslation\Hooks::addModules(Object(OutputPage), Object(SkinVector)) #1 /srv/mediawiki/php-master/includes/Hooks.php(234): Hooks::callHook('BeforePageDispl...', Array, Array, NULL, 'ContentTranslat...') #2 /srv/mediawiki/php-master/includes/OutputPage.php(2706): Hooks::runWithoutAbort('BeforePageDispl...', Array) #3 /srv/mediawiki/php-master/includes/exception/MWExceptionRenderer.php(136): OutputPage->output() #4 /srv/mediawiki/php-master/includes/exception/MWExceptionRenderer.php(53): MWExceptionRenderer::reportHTML(Object(Error)) #5 /srv/mediawiki/php-master/includes/exception/MWExceptionHandler.php(98): MWExceptionRenderer::output(Object(Error), 2) #6 /srv/mediawiki/php-master/includes/exception/MWExceptionHandler.php(172): MWExceptionHandler::report(Object(Error)) #7 /srv/mediawiki/php-master/ in /srv/mediawiki/php-master/extensions/ContentTranslation/includes/Hooks.php on line 96 (172.16.4.119)