Issue #3522955: add attribute classes.

Closes #3522955

src/Attribute/EntityBrowserDisplay.php

+<?php
+
+namespace Drupal\entity_browser\Attribute;
+
+use Drupal\Component\Plugin\Attribute\Plugin;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * Defines an entity browser display attribute object.
+ *
+ * @see hook_entity_browser_display_info_alter()
+ */
+#[\Attribute(\Attribute::TARGET_CLASS)]
+class EntityBrowserDisplay extends Plugin {
+  /**
+   * Constructs a new EntityBrowserDisplay instance.
+   *
+   * @param string $id
+   *   The plugin ID.
+   * @param \Drupal\Core\StringTranslation\TranslatableMarkup $label
+   *   The human-readable name of the display.
+   * @param \Drupal\Core\StringTranslation\TranslatableMarkup|null $description
+   *   (optional) A brief description of the display. This will be shown when
+   *   adding or configuring this display.
+   * @param bool $uses_route
+   *   Indicates that display uses route.
+   */
+  public function __construct(
+    public readonly string $id,
+    public readonly TranslatableMarkup $label,
+    public readonly ?TranslatableMarkup $description = NULL,
+    public bool $uses_route = FALSE,
+    public ?string $provider = NULL,
+  ) {}
+}