diff --git a/core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginBase.php b/core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginBase.php
index b81b6678e6..b5795c1bcd 100644
--- a/core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginBase.php
+++ b/core/lib/Drupal/Core/Entity/EntityReferenceSelection/SelectionPluginBase.php
@@ -119,6 +119,8 @@ public function entityQueryAlter(SelectInterface $query) { }
    *   The configuration array to be altered.
    *
    * @deprecated Scheduled for removal in Drupal 9.0.x.
+   *
+   * @see https://www.drupal.org/node/2870971
    */
   protected function resolveBackwardCompatibilityConfiguration(array &$configuration) {
     if (isset($this->defaultConfiguration()['handler_settings'])) {
@@ -130,7 +132,7 @@ protected function resolveBackwardCompatibilityConfiguration(array &$configurati
       if (!is_array($configuration['handler_settings'])) {
         throw new \InvalidArgumentException("The setting 'handler_settings' is reserved and cannot be used.");
       }
-      @trigger_error("Providing settings under 'handler_settings' is deprecated and will be removed before 9.0.0. Move the settings in the root of the configuration array.", E_USER_DEPRECATED);
+      @trigger_error("Providing settings under 'handler_settings' is deprecated and will be removed before 9.0.0. Move the settings in the root of the configuration array. See https://www.drupal.org/node/2870971.", E_USER_DEPRECATED);
 
       // Settings passed in the root level take precedence over BC settings.
       $configuration += $configuration['handler_settings'];
@@ -142,6 +144,8 @@ protected function resolveBackwardCompatibilityConfiguration(array &$configurati
    * Ensures a backward compatibility level configuration.
    *
    * @deprecated Scheduled for removal in Drupal 9.0.x.
+   *
+   * @see https://www.drupal.org/node/2870971
    */
   protected function ensureBackwardCompatibilityConfiguration() {
     // Synchronize back 'handler_settings'.