It seems b50c884 has caused or exposed a fatal error in MediaWiki core that affects ContentTranslation as can be seen in https://integration.wikimedia.org/ci/job/quibble-vendor-mysql-php70-docker/7190/console:
1) SpecialPageFatalTest::testSpecialPageDoesNotFatal with data set "ContentTranslationStats" (SpecialContentTranslationStats Object (...)) Error: Call to a member function getPrefixedDBkey() on null /workspace/src/includes/skins/SkinTemplate.php:181 /workspace/src/includes/skins/SkinTemplate.php:539 /workspace/src/extensions/ContentTranslation/specials/ContentTranslationSpecialPage.php:81 /workspace/src/extensions/ContentTranslation/specials/ContentTranslationSpecialPage.php:53 /workspace/src/tests/phpunit/includes/specials/SpecialPageExecutor.php:105 /workspace/src/tests/phpunit/includes/specials/SpecialPageExecutor.php:36 /workspace/src/tests/phpunit/structure/SpecialPageFatalTest.php:41 /workspace/src/tests/phpunit/MediaWikiTestCase.php:469 /workspace/src/maintenance/doMaintenance.php:94
It feels as if the title for the request context is not set properly.