PHPUnit 10 does not allow to skip (markTestSkipped) from data provider and count this as errors.
There were 2 PHPUnit errors: 1) MediaWiki\Tests\OutputTransform\Stages\HardenNFCTest::testShouldNotRun The data provider specified for MediaWiki\Tests\OutputTransform\Stages\HardenNFCTest::testShouldNotRun is invalid HydrateHeaderPlaceHolders should always run tests\phpunit\includes\OutputTransform\Stages\HardenNFCTest.php:49 2) MediaWiki\Tests\OutputTransform\Stages\HydrateHeaderPlaceholdersTest::testShouldNotRun The data provider specified for MediaWiki\Tests\OutputTransform\Stages\HydrateHeaderPlaceholdersTest::testShouldNotRun is invalid HydrateHeaderPlaceHolders should always run tests\phpunit\includes\OutputTransform\Stages\HydrateHeaderPlaceholdersTest.php:49