PluginManagerPass.php

<?php

namespace Drupal\Core\Plugin;

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

/**
 * Registers plugin managers to the plugin.cache_clearer service.
 */
class PluginManagerPass implements CompilerPassInterface {
    
    /**
     * {@inheritdoc}
     */
    public function process(ContainerBuilder $container) : void {
        foreach ($container->getDefinitions() as $service_id => $definition) {
            if (str_starts_with($service_id, 'plugin.manager.') && !$definition->hasTag('plugin_manager_cache_clear')) {
                if (is_subclass_of($definition->getClass(), '\\Drupal\\Component\\Plugin\\Discovery\\CachedDiscoveryInterface')) {
                    $definition->addTag('plugin_manager_cache_clear');
                }
            }
        }
    }

}