--- /dev/null
+<?php
+
+namespace Drupal\layout_builder_fieldblock_test\Plugin\Block;
+
+use Drupal\layout_builder\Plugin\Block\FieldBlock as LayoutBuilderFieldBlock;
+
+/**
+ * Provides test field block to test with Block UI.
+ *
+ * \Drupal\Tests\layout_builder\FunctionalJavascript\FieldBlockTest provides
+ * test coverage of complex AJAX interactions within certain field blocks.
+ * layout_builder_plugin_filter_block__block_ui_alter() removes certain blocks
+ * with 'layout_builder' as the provider. To make these blocks available during
+ * testing, this plugin uses the same deriver but each derivative will have a
+ * different provider.
+ *
+ * @Block(
+ * id = "field_block_test",
+ * deriver = "\Drupal\layout_builder\Plugin\Derivative\FieldBlockDeriver",
+ * )
+ *
+ * @see \Drupal\Tests\layout_builder\FunctionalJavascript\FieldBlockTest
+ * @see layout_builder_plugin_filter_block__block_ui_alter()
+ */
+class FieldBlock extends LayoutBuilderFieldBlock {
+
+}