UniversalLanguageSelector has been updated and no more has a 'uls-select-language' message. Hence the tests for SpellingDictionary fail with:
ResourcesTest::testMissingMessages Message 'uls-select-language' required by 'ext.SpellingDictionary.viewByLanguage' must exist Failed asserting that false is true. src/tests/phpunit/structure/ResourcesTest.php:102 src/tests/phpunit/MediaWikiTestCase.php:399 src/maintenance/doMaintenance.php:111