Drupal 8: Entity browser custom form field

<?php 
form['entity_browser'] = [
      '#type' => 'container',
      //'#parents' => ['content_link_wrapper'],
      //'#weight' => -3,
      'widget' => [
        '#title' => t('Content Link'),
        '#description' => t('The content to be linked in the menu.'),
        '#field_name' => 'content_link',
        '#field_parents' => [],
        '#required' => TRUE,
        '#parents' => ['content_link'],
        '#tree' => TRUE,
        '#id' => 'edit-content-link',
        '#type' => 'details',
        '#open' => TRUE,
        'target_id' => [
          '#type' => 'hidden',
          '#id' => 'edit-content-link-target-id',
          '#attributes' => [
            'id' => 'edit-content-link-target-id',
          ],
          '#default_value' => "",
          '#ajax' => [
            'callback' => [
              'Drupal\entity_browser\Plugin\Field\FieldWidget\EntityReferenceBrowserWidget',
              'updateWidgetCallback',
            ],
            'wrapper' => 'edit-content-link',
            'event' => 'entity_browser_value_updated',
          ],
        ],
        'entity_browser' => [
          '#type' => 'entity_browser',
          '#entity_browser' => 'experience_cms_entity_browser',
          //'#cardinality' => 1,
          //'#selection_mode' => 'selection_edit',
          //'#default_value' => [],
          '#entity_browser_validators' => [
            'entity_type' => [
              'type' => 'node',
            ],
          ],
          '#custom_hidden_id' => 'edit-content-link-target-id',
          '#process' => [
            [
              '\Drupal\entity_browser\Element\EntityBrowserElement',
              'processEntityBrowser',
            ],
            [
              'Drupal\entity_browser\Plugin\Field\FieldWidget\EntityReferenceBrowserWidget',
              'processEntityBrowser',
            ],
          ]
        ],
        'current' => [
          '#theme_wrappers' => ['container'],
          '#attributes' => [
            'class' => 'entities-list',
          ],
          'items' => [],
        ],
        '#after_build' => [
          [
            'Drupal\entity_browser\Plugin\Field\FieldWidget\EntityReferenceBrowserWidget',
            'afterBuild',
          ],
        ],
        '#attached' => [
          'library' => [
            'entity_browser/entity_reference',
          ],
        ],
      ],
    ];
?>

OR easy one

<?php 
form['entity_browser'] = [
      '#type' => 'container',
      '#id' => 'edit-content-link-wrapper',
      '#attributes' => [
        'id' => 'edit-content-link-wrapper',
      ],
      'target_id' => [
        '#type' => 'hidden',
        '#id' => 'edit-content-link-target-id',
        '#attributes' => [
          'id' => 'edit-content-link-target-id',
        ],
        '#default_value' => "",
        '#ajax' => [
          'callback' => [
            'Drupal\entity_browser\Plugin\Field\FieldWidget\EntityReferenceBrowserWidget',
            'updateWidgetCallback',
          ],
          'wrapper' => 'edit-content-link-wrapper',
          'event' => 'entity_browser_value_updated',
        ],
      ],
      'entity_browser' => [
        '#type' => 'entity_browser',
        '#entity_browser' => 'experience_cms_entity_browser',
        '#entity_browser_validators' => [
          'entity_type' => [
            'type' => 'node',
          ],
        ],
        '#custom_hidden_id' => 'edit-content-link-target-id',
        '#process' => [
          [
            '\Drupal\entity_browser\Element\EntityBrowserElement',
            'processEntityBrowser',
          ],
          [
            'Drupal\entity_browser\Plugin\Field\FieldWidget\EntityReferenceBrowserWidget',
            'processEntityBrowser',
          ],
        ]
      ],
    ];