diff --git a/core/modules/views/src/Plugin/views/field/FieldHandlerInterface.php b/core/modules/views/src/Plugin/views/field/FieldHandlerInterface.php
index 01769b5..b25e419 100644
--- a/core/modules/views/src/Plugin/views/field/FieldHandlerInterface.php
+++ b/core/modules/views/src/Plugin/views/field/FieldHandlerInterface.php
@@ -168,7 +168,9 @@ public function preRender(&$values);
    *   The values retrieved from a single row of a view's query result.
    *
    * @return string|\Drupal\Component\Utility\SafeStringInterface
-   *   The rendered output.
+   *   The rendered output. If the output is safe it will be wrapped in a
+   *   \Drupal\Core\Render\SafeString object. If it is empty or unsafe it will
+   *   be a string.
    *
    */
   public function render(ResultRow $values);
@@ -203,7 +205,9 @@ public function postRender(ResultRow $row, $output);
    *   The values retrieved from a single row of a view's query result.
    *
    * @return string|\Drupal\Component\Utility\SafeStringInterface
-   *   The advanced rendered output.
+   *   The advanced rendered output. If the output is safe it will be wrapped in
+   *   a \Drupal\Core\Render\SafeString object. If it is empty or unsafe it will
+   *   be a string.
    *
    */
   public function advancedRender(ResultRow $values);
@@ -237,29 +241,13 @@ public function isValueEmpty($value, $empty_zero, $no_skip_empty = TRUE);
    *     - html: Make sure that the html is correct.
    *
    * @return string|\Drupal\Component\Utility\SafeStringInterface
-   *   The rendered output.
+   *   The rendered output. If the output is safe it will be wrapped in a
+   *   \Drupal\Core\Render\SafeString object. If it is empty or unsafe it will
+   *   be a string.
    */
   public function renderText($alter);
 
   /**
-   * Trims the field down to the specified length.
-   *
-   * @param array $alter
-   *   The alter array of options to use.
-   *     - max_length: Maximum length of the string, the rest gets truncated.
-   *     - word_boundary: Trim only on a word boundary.
-   *     - ellipsis: Show an ellipsis (…) at the end of the trimmed string.
-   *     - html: Make sure that the html is correct.
-   *
-   * @param string $value
-   *   The string which should be trimmed.
-   *
-   * @return string
-   *   The rendered trimmed string.
-   */
-  public function renderTrimText($alter, $value);
-
-  /**
    * Gets the 'render' tokens to use for advanced rendering.
    *
    * This runs through all of the fields and arguments that
@@ -281,7 +269,9 @@ public function getRenderTokens($item);
    *   Holds single row of a view's result set.
    *
    * @return string|\Drupal\Component\Utility\SafeStringInterface
-   *   Returns rendered output of the given theme implementation.
+   *   Returns rendered output of the given theme implementation. If the output
+   *   is safe it will be wrapped in a \Drupal\Core\Render\SafeString object. If
+   *   it is empty or unsafe it will be a string.
    */
   function theme(ResultRow $values);
 
diff --git a/core/modules/views/src/Plugin/views/field/FieldPluginBase.php b/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
index e92278f..973916b 100644
--- a/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
+++ b/core/modules/views/src/Plugin/views/field/FieldPluginBase.php
@@ -1324,9 +1324,22 @@ protected function renderAltered($alter, $tokens) {
   }
 
   /**
-   * {@inheritdoc}
+   * Trims the field down to the specified length.
+   *
+   * @param array $alter
+   *   The alter array of options to use.
+   *     - max_length: Maximum length of the string, the rest gets truncated.
+   *     - word_boundary: Trim only on a word boundary.
+   *     - ellipsis: Show an ellipsis (…) at the end of the trimmed string.
+   *     - html: Make sure that the html is correct.
+   *
+   * @param string $value
+   *   The string which should be trimmed.
+   *
+   * @return string
+   *   The rendered trimmed string.
    */
-  public function renderTrimText($alter, $value) {
+  protected function renderTrimText($alter, $value) {
     if (!empty($alter['strip_tags'])) {
       // NOTE: It's possible that some external fields might override the
       // element type.