Ben Mullins
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
   */
  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
    /** @var \Drupal\link\LinkItemInterface $item */
+    $default_values = [];
    $item = $items[$delta];
+    $default_values = !empty($item->getFieldDefinition()->getDefaultValueLiteral()) ? $item->getFieldDefinition()->getDefaultValueLiteral() : [];
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
    parent::flagErrors($items, $violations, $form, $form_state);
  }

+  /**
+   * {@inheritdoc}
+   *
+   * We duplicate extractFormValues()
+   * so that it does not call filterEmptyItems()
+   * when in the default value form.
+   * This way, we can save a default value with only a text and not URI.
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+      $key_exists = NULL;
+      $values = NestedArray::getValue($form_state->getValues(), $path, $key_exists);
+
+      if ($key_exists) {
+        // Account for drag-and-drop reordering if needed.
+        if (!$this->handlesMultipleValues()) {
+          // Remove the 'value' of the 'add more' button.
+          unset($values['add_more']);
+
+          // The original delta, before drag-and-drop reordering, is needed to
+          // route errors to the correct form element.
+          foreach ($values as $delta => &$value) {
+            $value['_original_delta'] = $delta;
+            if ($value['uri'] == NULL && $value['title'] == NULL) {
+              unset($values[$delta]);
+            }
--- a/core/modules/link/src/Plugin/Validation/Constraint/LinkTypeConstraintValidator.php
+++ b/core/modules/link/src/Plugin/Validation/Constraint/LinkTypeConstraintValidator.php
          $uri_is_valid = FALSE;
        }
      }
-
-      if (!$uri_is_valid) {
+      if (isset($url) && $url !== NULL && !$uri_is_valid) {
--- a/core/modules/link/src/Plugin/Validation/Constraint/LinkTypeConstraintValidator.php
+++ b/core/modules/link/src/Plugin/Validation/Constraint/LinkTypeConstraintValidator.php
          $uri_is_valid = FALSE;
        }
      }
-
-      if (!$uri_is_valid) {
--- a/core/modules/link/tests/src/Functional/LinkFieldTest.php
+++ b/core/modules/link/tests/src/Functional/LinkFieldTest.php
    return (string) $output;
  }

+  /**
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
   */
  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
    /** @var \Drupal\link\LinkItemInterface $item */
+    $default_values = [];
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
      '#type' => 'textfield',
      '#title' => $this->t('Link text'),
      '#placeholder' => $this->getSetting('placeholder_title'),
-      '#default_value' => isset($items[$delta]->title) ? $items[$delta]->title : NULL,
+      '#default_value' => isset($default_values[$delta]['title']) ? $default_values[$delta]['title'] : NULL,
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+        // Let the widget massage the submitted values.
+        $values = $this->massageFormValues($values, $form, $form_state);
+        // Assign the values and remove the empty ones.
+        $items->setValue($values);
+
+        // Put delta mapping in $form_state, so that flagErrors() can use it.
+        $field_state = static::getWidgetState($form['#parents'], $field_name, $form_state);
+        foreach ($items as $delta => $item) {
+          $field_state['original_deltas'][$delta] = isset($item->_original_delta) ? $item->_original_delta : $delta;
+          unset($item->_original_delta, $item->_weight);
+        }
+        static::setWidgetState($form['#parents'], $field_name, $form_state, $field_state);
+      }
+    }
+    else {
+      parent::extractFormValues($items, $form, $form_state);
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
      '#type' => 'textfield',
      '#title' => $this->t('Link text'),
      '#placeholder' => $this->getSetting('placeholder_title'),
-      '#default_value' => isset($items[$delta]->title) ? $items[$delta]->title : NULL,
+      '#default_value' => isset($default_values[$delta]['title']) ? $default_values[$delta]['title'] : NULL,
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
    parent::flagErrors($items, $violations, $form, $form_state);
  }

+  /**
+   * {@inheritdoc}
+   *
+   * Override extractFormValues() so that it does not call filterEmptyItems()
+   * when in the default value form. This makes it possible to save a default
+   * value for "Link text" without requiring a default value for "URL".
+   */
+  public function extractFormValues(FieldItemListInterface $items, array $form, FormStateInterface $form_state) {
+    if (!$this->isDefaultValueWidget($form_state)) {
+      parent::extractFormValues($items, $form, $form_state);
+    }
+    else {