diff --git a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
index 9af176c..64fdb19 100644
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
@@ -239,6 +239,28 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
       // title of the 'uri' element.
       if ($this->getFieldSetting('title') == DRUPAL_DISABLED) {
         $element['uri']['#title'] = $element['#title'];
+        // By default the field description is added to the title field. Since
+        // the title field is disabled, we add the description, if given, to the
+        // uri element instead.
+        if (!empty($element['#description'])) {
+          if (empty($element['uri']['#description'])) {
+            $element['uri']['#description'] = $element['#description'];
+          }
+          else {
+            // If we have the description of the type of field together with
+            // the user provided description, we want to make a distinction
+            // between "core help text" and "user entered help text". To make
+            // this distinction more clear, we put them in an unordered list.
+            $element['uri']['#description'] = [
+              '#theme' => 'item_list',
+              '#items' => [
+                // User description first to avoid screen reader users to skip.
+                $element['#description'],
+                $element['uri']['#description'],
+              ],
+            ];
+          }
+        }
       }
       // Otherwise wrap everything in a details element.
       else {
diff --git a/core/modules/link/tests/src/Functional/LinkFieldUITest.php b/core/modules/link/tests/src/Functional/LinkFieldUITest.php
index eeed78c..0f37f38 100644
--- a/core/modules/link/tests/src/Functional/LinkFieldUITest.php
+++ b/core/modules/link/tests/src/Functional/LinkFieldUITest.php
@@ -52,41 +52,102 @@ function testFieldUI() {
 
     // Add a link field to the newly-created type. It defaults to allowing both
     // internal and external links.
-    $label = $this->randomMachineName();
+    $label = 'link_field_label';
+    $description = 'link field description';
     $field_name = Unicode::strtolower($label);
-    $this->fieldUIAddNewField($type_path, $field_name, $label, 'link');
+    $field_edit = [
+      'description' => $description,
+    ];
+    $this->fieldUIAddNewField($type_path, $field_name, $label, 'link', [], $field_edit);
 
     // Load the formatter page to check that the settings summary does not
     // generate warnings.
     // @todo Mess with the formatter settings a bit here.
     $this->drupalGet("$type_path/display");
-    $this->assertText(t('Link text trimmed to @limit characters', array('@limit' => 80)));
-
-    // Test the help text displays when the link field allows both internal and
-    // external links.
-    $this->drupalLogin($this->drupalCreateUser(['create ' . $type->id() . ' content']));
-    $this->drupalGet($add_path);
-    $this->assertRaw('You can also enter an internal path such as <em class="placeholder">/node/add</em> or an external URL such as <em class="placeholder">http://example.com</em>.');
-
-    // Log in an admin to set up the next content type.
+    $this->assertText(t('Link text trimmed to @limit characters', ['@limit' => 80]));
+
+    // There are many combinations of UI settings, where the description should
+    // show: variation on internal, external, both; cardinality (where the
+    // fieldset is hidden or used); and link text shown (required or optional)
+    // or disabled. There are two descriptions: field and URL help text.
+    $cardinalities = [1, 2];
+    $title_settings = [
+      DRUPAL_DISABLED,
+      DRUPAL_OPTIONAL,
+    ];
+    $link_types = [
+      LinkItemInterface::LINK_EXTERNAL,
+      LinkItemInterface::LINK_GENERIC,
+      LinkItemInterface::LINK_INTERNAL,
+    ];
+    $help_texts = [
+      LinkItemInterface::LINK_EXTERNAL => 'This must be an external URL such as <em class="placeholder">http://example.com</em>.',
+      LinkItemInterface::LINK_GENERIC => 'You can also enter an internal path such as <em class="placeholder">/node/add</em> or an external URL such as <em class="placeholder">http://example.com</em>. Enter <em class="placeholder">&lt;front&gt;</em> to link to the front page.',
+      LinkItemInterface::LINK_INTERNAL => rtrim(\Drupal::url('<front>', [], ['absolute' => TRUE]), '/'),
+    ];
+
+    // Log in an admin to set up a content type for this test.
     $this->drupalLogin($this->adminUser);
 
-    // Add a different content type.
+    // Add a new content type.
     $type = $this->drupalCreateContentType();
     $type_path = 'admin/structure/types/manage/' . $type->id();
     $add_path = 'node/add/' . $type->id();
 
-    // Add a link field to the newly-created type. Specify it must allow
-    // external only links.
-    $label = $this->randomMachineName();
-    $field_name = Unicode::strtolower($label);
-    $field_edit = ['settings[link_type]' => LinkItemInterface::LINK_EXTERNAL];
-    $this->fieldUIAddNewField($type_path, $field_name, $label, 'link', array(), $field_edit);
-
-    // Test the help text displays when link allows only external links.
+    $field_count = 0;
+    // Test all variations of link types on all cardinalities.
+    foreach ($cardinalities as $cardinality) {
+      foreach ($link_types as $link_type) {
+        // Now, test this with both the title enabled and disabled.
+        foreach ($title_settings as $title_setting) {
+          // Both test empty descriptions and not empty descriptions.
+          foreach ([TRUE, FALSE] as $description_enabled) {
+            $field_count++;
+
+            // Create a field for this content type with the current cardinality
+            // and link field settings.
+            $label = "link_field_label_$field_count";
+            $description = '<img src="http://example.com" />link field description with html ' . $field_count;
+            $field_name = Unicode::strtolower($label);
+            $storage_edit = ['cardinality_number' => $cardinality];
+            $field_edit = [
+              'settings[link_type]' => $link_type,
+              'description' => $description_enabled ? $description : '',
+              'settings[title]' => $title_setting,
+            ];
+            $this->fieldUIAddNewField($type_path, $field_name, $label, 'link', $storage_edit, $field_edit);
+          }
+        }
+      }
+    }
+
+    // Log in a user that is allowed to create this content type, see if
+    // the user can see the expected help text.
     $this->drupalLogin($this->drupalCreateUser(['create ' . $type->id() . ' content']));
+
     $this->drupalGet($add_path);
-    $this->assertRaw('This must be an external URL such as <em class="placeholder">http://example.com</em>.');
+
+    $field_count = 0;
+    // Test all variations of link types on all cardinalities.
+    foreach ($cardinalities as $cardinality) {
+      foreach ($link_types as $link_type) {
+        // Now, test this with both the title enabled and disabled.
+        foreach ($title_settings as $title_setting) {
+          // Both test empty descriptions and not empty descriptions.
+          foreach ([TRUE, FALSE] as $description_enabled) {
+            $field_count++;
+            $description = '<img src="http://example.com" />link field description with html ' . $field_count;
+            // Check that the help texts we assume should be there, is there.
+            $this->assertRaw($help_texts[$link_type]);
+            // Also assert that the description we made is here, no matter what
+            // the cardinality or link setting.
+            if ($description_enabled) {
+              $this->assertRaw($description);
+            }
+          }
+        }
+      }
+    }
   }
 
 }
diff --git a/core/modules/menu_link_content/src/Tests/MenuLinkContentFormTest.php b/core/modules/menu_link_content/src/Tests/MenuLinkContentFormTest.php
index 1bdc927..bf4ba43 100644
--- a/core/modules/menu_link_content/src/Tests/MenuLinkContentFormTest.php
+++ b/core/modules/menu_link_content/src/Tests/MenuLinkContentFormTest.php
@@ -37,6 +37,8 @@ public function testMenuLinkContentForm() {
     $element = $this->xpath('//select[@id = :id]/option[@selected]', array(':id' => 'edit-menu-parent'));
     $this->assertTrue($element, 'A default menu parent was found.');
     $this->assertEqual('admin:', $element[0]['value'], '<Administration> menu is the parent.');
+    // Test that the field description is present.
+    $this->assertRaw('The location this menu link points to.');
 
     $this->drupalPostForm(
       NULL,
diff --git a/core/modules/shortcut/src/Tests/ShortcutLinksTest.php b/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
index 679f89b..85c2cba4 100644
--- a/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
+++ b/core/modules/shortcut/src/Tests/ShortcutLinksTest.php
@@ -62,6 +62,11 @@ public function testShortcutLinkAdd() {
       '/admin/config/system/site-information',
     ];
 
+    // Test the add shortcut form UI. Test that the base field description is
+    // there.
+    $this->drupalGet('admin/config/user-interface/shortcut/manage/' . $set->id() . '/add-link');
+    $this->assertRaw('The location this shortcut points to.');
+
     // Check that each new shortcut links where it should.
     foreach ($test_cases as $test_path) {
       $title = $this->randomMachineName();