9 files declare their use of Parameter in Zircon Profile 8

container9.php in vendor/symfony/dependency-injection/Tests/Fixtures/containers/container9.php

GraphvizDumper.php in vendor/symfony/dependency-injection/Dumper/GraphvizDumper.php

KernelTestBase.php in core/modules/simpletest/src/KernelTestBase.php

Contains \Drupal\simpletest\KernelTestBase.

OptimizedPhpArrayDumper.php in core/lib/Drupal/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumper.php

Contains \Drupal\Component\DependencyInjection\Dumper\OptimizedPhpArrayDumper.

OptimizedPhpArrayDumperTest.php in core/tests/Drupal/Tests/Component/DependencyInjection/Dumper/OptimizedPhpArrayDumperTest.php

Contains \Drupal\Tests\Component\DependencyInjection\Dumper\OptimizedPhpArrayDumperTest.

ParameterTest.php in vendor/symfony/dependency-injection/Tests/ParameterTest.php

PhpDumper.php in vendor/symfony/dependency-injection/Dumper/PhpDumper.php

XmlDumper.php in vendor/symfony/dependency-injection/Dumper/XmlDumper.php

YamlDumper.php in vendor/symfony/dependency-injection/Dumper/YamlDumper.php