diff --git a/src/Controller/RdfMappingsReportController.php b/src/Controller/RdfMappingsReportController.php
index 2b3e3a31..f0cb65e5 100644
--- a/src/Controller/RdfMappingsReportController.php
+++ b/src/Controller/RdfMappingsReportController.php
@@ -3,6 +3,8 @@
 namespace Drupal\islandora\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\taxonomy\Entity\Term;
 
 /**
  * RDF mappings report controller.
@@ -20,6 +22,23 @@ class RdfMappingsReportController extends ControllerBase {
     $markup = '';
     $entity_types = ['node', 'media'];
 
+    $namespaces = rdf_get_namespaces();
+    $namespaces_table_rows = [];
+    foreach ($namespaces as $alias => $namespace_uri) {
+      $namespaces_table_rows[] = [$alias, $namespace_uri];
+    }
+    $namespaces_table_header = [t('Namespace alias'), t('Namespace URI')];
+    $namespaces_table = [
+      '#theme' => 'table',
+      '#header' => $namespaces_table_header,
+      '#rows' => $namespaces_table_rows,
+    ];
+    $namespaces_table_markup = \Drupal::service('renderer')->render($namespaces_table);
+
+    $markup .= '<details><summary>' . t('RDF namespaces used in field mappings') .
+      '</summary><div class="details-wrapper">' . $namespaces_table_markup . '</div></details>';
+
+    $markup .= '<h2>' . t('Field mappings') . '</h2>';
     foreach ($entity_types as $entity_type) {
       $bundles = \Drupal::service('entity_type.bundle.info')->getBundleInfo($entity_type);
       foreach ($bundles as $name => $attr) {
@@ -51,21 +70,47 @@ class RdfMappingsReportController extends ControllerBase {
       }
     }
 
-    $markup .= '<h3>RDF namespaces</h3>';
-    $namespaces = rdf_get_namespaces();
-    $namespaces_table_rows = [];
-    foreach ($namespaces as $alias => $namespace_uri) {
-      $namespaces_table_rows[] = [$alias, $namespace_uri];
+    // Taxonomy terms with external URIs.
+    $markup .= '<h2>' . t('Taxonomy terms with external URIs') . '</h2>';
+    $utils = \Drupal::service('islandora.utils');
+    $vocabs = Vocabulary::loadMultiple();
+    foreach ($vocabs as $vid => $vocab) {
+      $vocab_table_header = [];
+      $vocab_table_rows = [];
+      $markup .= '<h3>' . $vocab->label() . ' (' . $vid . ')</h3>';
+      $terms = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree($vid);
+      if (count($terms) == 0) {
+        $vocab_table_rows[] = [t('No terms in this vocabulary.')];
+        $vocab_table = [
+          '#theme' => 'table',
+          '#header' => $vocab_table_header,
+          '#rows' => $vocab_table_rows,
+        ];
+        $vocab_table_markup = \Drupal::service('renderer')->render($vocab_table);
+        $markup .= $vocab_table_markup;
+      }
+      else {
+        $vocab_table_header = [t('Term'), t('Term ID'), t('External URI')];
+        $vocab_table_rows = [];
+        foreach ($terms as $t) {
+          $term = Term::load($t->tid);
+          $uri = $utils->getUriForTerm($term);
+          if (is_null($uri)) {
+            $vocab_table_rows[] = [$term->getName(), $term->id(), t('None')];
+          }
+          else {
+            $vocab_table_rows[] = [$term->getName(), $term->id(), $uri];
+          }
+        }
+        $vocab_table = [
+          '#theme' => 'table',
+          '#header' => $vocab_table_header,
+          '#rows' => $vocab_table_rows,
+        ];
+      }
+      $vocab_table_markup = \Drupal::service('renderer')->render($vocab_table);
+      $markup .= $vocab_table_markup;
     }
-    $namespaces_table_header = [t('Namespace alias'), t('Namespace URI')];
-    $namespaces_table = [
-      '#theme' => 'table',
-      '#header' => $namespaces_table_header,
-      '#rows' => $namespaces_table_rows,
-    ];
-    $namespaces_table_markup = \Drupal::service('renderer')->render($namespaces_table);
-
-    $markup .= $namespaces_table_markup;
 
     return ['#markup' => $markup];
   }
diff --git a/src/IslandoraUtils.php b/src/IslandoraUtils.php
index 1d337796..08d02e3a 100644
--- a/src/IslandoraUtils.php
+++ b/src/IslandoraUtils.php
@@ -265,7 +265,7 @@ class IslandoraUtils {
   }
 
   /**
-   * Gets the taxonomy term associated with an external uri.
+   * Gets the external uri associated with a taxonomy term.
    *
    * @param \Drupal\taxonomy\TermInterface $term
    *   Taxonomy term.