symfony/phpunit-bridge defines a convention where adding @group legacy on a test (either by adding it on the method or on the class as PHPUnit considers that a @group added on a class applies to all tests defined in that class) disables the reporting of deprecations in that test, as this test is about covering the legacy behavior (and so using deprecated APIs is expected).

phpstan/phpstan-deprecation-rules#99 has added an extension point allowing to implement such feature. It would be great to provide an implementation of the interface following this convention.