attempt to add the typed relation prefix to the formatted output

src/Plugin/Field/FieldFormatter/SolrFacetTextFieldFormatter.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\solr_facet_field_formatter\Plugin\Field\FieldFormatter;
 
+use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Field\FieldItemInterface;
@@ -228,11 +229,50 @@ class SolrFacetTextFieldFormatter extends FormatterBase implements ContainerFact
       $url = Url::fromUserInput($path, ['query' => $query]);
       $link = Link::fromTextAndUrl($value, $url);
       $element[$delta] = [$link->toRenderable()];
+
+      // For Islandora typed relation fields, show the relation type as a
+      // prefix outside the link (e.g. "Author: Jane Doe"). Set on the wrapper
+      // element so it renders before the link, not inside the anchor text.
+      $prefix = $this->getTypedRelationPrefix($item);
+      if ($prefix !== NULL) {
+        $element[$delta]['#prefix'] = new FormattableMarkup('@prefix: ', ['@prefix' => $prefix]);
+      }
     }
 
     return $element;
   }
 
+  /**
+   * Builds the relation-type prefix for an Islandora typed relation item.
+   *
+   * The check is based on the field type id so the module has no hard
+   * dependency on controlled_access_terms; the typed relation methods are only
+   * called once the field type is confirmed.
+   *
+   * @param \Drupal\Core\Field\FieldItemInterface $item
+   *   The field item.
+   *
+   * @return string|null
+   *   The human readable relation type label, or NULL if the item is not a
+   *   typed relation or has no relation type set.
+   */
+  protected function getTypedRelationPrefix(FieldItemInterface $item) {
+    if ($item->getFieldDefinition()->getType() !== 'typed_relation') {
+      return NULL;
+    }
+
+    $rel_type_key = $item->rel_type;
+    if (empty($rel_type_key)) {
+      return NULL;
+    }
+
+    // getRelTypes() maps the stored key to a human readable label.
+    $rel_types = $item->getRelTypes();
+    $label = $rel_types[$rel_type_key] ?? $rel_type_key;
+
+    return $label !== '' ? $label : NULL;
+  }
+
   /**
    * The available "Facet value" options for the settings form.
    *