Use service contracts to persist entities in favour of Magento\Email\Model\Template::load() method

Use service contracts to persist entities in favour of Magento\Email\Model\BackendTemplate::delete() method

Method Magento\Email\Controller\Adminhtml\Email\Template\Preview::execute() should return Magento\Framework\App\ResponseInterface|Magento\Framework\Controller\ResultInterface but return statement is missing.

Use service contracts to persist entities in favour of $this(Magento\Email\Model\AbstractTemplate)::load() method

Use service contracts to persist entities in favour of $this(Magento\Email\Model\Template)::load() method

Method Magento\Email\Setup\Patch\Data\FlagLegacyTemplates::apply() should return $this(Magento\Email\Setup\Patch\Data\FlagLegacyTemplates) but return statement is missing.

Class Magento\Email\Test\Fixture\FileTransport implements unknown interface Magento\TestFramework\Fixture\RevertibleDataFixtureInterface.

Property Magento\Email\Test\Fixture\FileTransport::$dataProcessor has unknown class Magento\TestFramework\Fixture\Data\ProcessorInterface as its type.

Parameter $dataProcessor of method Magento\Email\Test\Fixture\FileTransport::__construct() has invalid type Magento\TestFramework\Fixture\Data\ProcessorInterface.