diff -u b/core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTid.php b/core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTid.php
--- b/core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTid.php
+++ b/core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTid.php
@@ -29,6 +29,7 @@
    *
    * @var array|null
    */
+  // @codingStandardsIgnoreLine
   public $validated_exposed_input = NULL;
 
   /**
@@ -73,6 +74,7 @@
     $this->vocabularyStorage = $vocabulary_storage;
     $this->termStorage = $term_storage;
     if (!$current_user) {
+      // @codingStandardsIgnoreLine
       @trigger_error('The current_user service must be passed to ' . __NAMESPACE__ . '\TaxonomyIndexTid::__construct(). It was added in drupal:8.9.0 and will be required before drupal:10.0.0.', E_USER_DEPRECATED);
       $current_user = \Drupal::service('current_user');
     }
@@ -135,6 +137,9 @@
     return $entity_ids;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function hasExtraOptions() {
     return TRUE;
   }
@@ -146,6 +151,9 @@
     return $this->valueOptions;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function defineOptions() {
     $options = parent::defineOptions();
 
@@ -158,6 +166,9 @@
     return $options;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function buildExtraOptionsForm(&$form, FormStateInterface $form_state) {
     $vocabularies = $this->vocabularyStorage->loadMultiple();
     $options = [];
@@ -186,7 +197,10 @@
     $form['type'] = [
       '#type' => 'radios',
       '#title' => $this->t('Selection type'),
-      '#options' => ['select' => $this->t('Dropdown'), 'textfield' => $this->t('Autocomplete')],
+      '#options' => [
+        'select' => $this->t('Dropdown'),
+        'textfield' => $this->t('Autocomplete'),
+      ],
       '#default_value' => $this->options['type'],
     ];
 
@@ -202,6 +216,9 @@
     ];
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function valueForm(&$form, FormStateInterface $form_state) {
     $vocabulary = $this->getVocabulary();
     if (empty($vocabulary) && $this->options['limit']) {
@@ -250,7 +267,7 @@
     }
 
     if (!$form_state->get('exposed')) {
-      // Retain the helper option
+      // Retain the helper option.
       $this->helper->buildOptionsForm($form, $form_state);
 
       // Show help text if not exposed to end users.
@@ -282,6 +299,9 @@
     return $form_value;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function getFormValueOptions() {
     if (!empty($this->options['hierarchy']) && $this->options['limit']) {
       return $this->getFormValueOptionsWithHierarchyAndLimit();
@@ -369,6 +389,9 @@
     }
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function valueValidate($form, FormStateInterface $form_state) {
     // We only validate if they've chosen the text field style.
     if ($this->options['type'] != 'textfield') {
@@ -384,6 +407,9 @@
     $form_state->setValue(['options', 'value'], $tids);
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function acceptExposedInput($input) {
     if (empty($this->options['exposed'])) {
       return TRUE;
@@ -396,7 +422,7 @@
     }
 
     // If view is an attachment and is inheriting exposed filters, then assume
-    // exposed input has already been validated
+    // exposed input has already been validated.
     if (!empty($this->view->is_attachment) && $this->view->display_handler->usesExposed()) {
       $this->validated_exposed_input = (array) $this->view->exposed_raw_input[$this->options['expose']['identifier']];
     }
@@ -423,6 +449,9 @@
     return $rc;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function validateExposed(&$form, FormStateInterface $form_state) {
     if (empty($this->options['exposed'])) {
       return;
@@ -455,8 +484,11 @@
     }
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function valueSubmit($form, FormStateInterface $form_state) {
-    // prevent array_filter from messing up our arrays in parent submit.
+    // Prevent array_filter from messing up our arrays in parent submit.
     $term_ids = $form_state->getValue(['options', 'value']);
 
     $uuids = [];
@@ -467,6 +499,9 @@
     $form_state->setValue(['options', 'value'], $uuids);
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function buildExposeForm(&$form, FormStateInterface $form_state) {
     parent::buildExposeForm($form, $form_state);
     if ($this->options['type'] != 'select') {
@@ -479,8 +514,11 @@
     ];
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function adminSummary() {
-    // set up $this->valueOptions for the parent summary
+    // Set up $this->valueOptions for the parent summary.
     $this->valueOptions = [];
 
     if ($this->value) {
@@ -526,7 +564,7 @@
   /**
    * Get the vocabulary entity given a vocabulary ID.
    *
-   * @return \Drupal\taxonomy\VocabularyInterface
+   * @return \Drupal\Core\Entity\EntityInterface
    *   The vocabulary matching the given vocabulary ID.
    */
   protected function getVocabulary() {
diff -u b/core/modules/taxonomy/tests/src/Functional/Views/TaxonomyIndexTidUiTest.php b/core/modules/taxonomy/tests/src/Functional/Views/TaxonomyIndexTidUiTest.php
--- b/core/modules/taxonomy/tests/src/Functional/Views/TaxonomyIndexTidUiTest.php
+++ b/core/modules/taxonomy/tests/src/Functional/Views/TaxonomyIndexTidUiTest.php
@@ -57,6 +57,8 @@
 
   /**
    * {@inheritdoc}
+   *
+   * @throws \Drupal\Core\Entity\EntityStorageException
    */
   protected function setUp($import_test_views = TRUE, $modules = []): void {
     parent::setUp($import_test_views, $modules);
@@ -78,7 +80,7 @@
     // - term 1.1
     // term 2.0
     // - term 2.1
-    // - term 2.2
+    // - term 2.2.
     for ($i = 0; $i < 3; $i++) {
       for ($j = 0; $j <= $i; $j++) {
         $this->terms[$i][$j] = $term = Term::create([
@@ -99,7 +101,11 @@
 
   /**
    * Tests the filter UI.
+   *
+   * @throws \Behat\Mink\Exception\ElementNotFoundException
+   * @throws \Drupal\Core\Entity\EntityStorageException
    */
+  // @codingStandardsIgnoreLine
   public function testFilterUI() {
     $this->drupalGet('admin/structure/views/nojs/handler/test_filter_taxonomy_index_tid/default/filter/tid');
 
@@ -143,6 +149,10 @@
 
   /**
    * Tests exposed taxonomy filters.
+   *
+   * @throws \Behat\Mink\Exception\ResponseTextException
+   * @throws \Behat\Mink\Exception\ExpectationException
+   * @throws \Drupal\Core\Entity\EntityMalformedException
    */
   public function testExposedFilter() {
     $node_type = $this->drupalCreateContentType(['type' => 'page']);
@@ -280,6 +290,8 @@
 
   /**
    * Tests exposed grouped taxonomy filters.
+   *
+   * @throws \Behat\Mink\Exception\ResponseTextException
    */
   public function testExposedGroupedFilter() {
     // Create a content type with a taxonomy field.
@@ -297,9 +309,18 @@
 
     $this->drupalGet('/admin/structure/views/nojs/handler/test_taxonomy_exposed_grouped_filter/page_1/filter/field_views_testing_tags_target_id');
     $edit = [
-      'options[group_info][group_items][1][value][]' => [$this->terms[0][0]->id(), $this->terms[1][0]->id()],
-      'options[group_info][group_items][2][value][]' => [$this->terms[1][0]->id(), $this->terms[2][0]->id()],
-      'options[group_info][group_items][3][value][]' => [$this->terms[2][0]->id(), $this->terms[0][0]->id()],
+      'options[group_info][group_items][1][value][]' => [
+        $this->terms[0][0]->id(),
+        $this->terms[1][0]->id(),
+      ],
+      'options[group_info][group_items][2][value][]' => [
+        $this->terms[1][0]->id(),
+        $this->terms[2][0]->id(),
+      ],
+      'options[group_info][group_items][3][value][]' => [
+        $this->terms[2][0]->id(),
+        $this->terms[0][0]->id(),
+      ],
     ];
     $this->submitForm($edit, 'Apply');
     $this->submitForm([], 'Save');
@@ -324,6 +345,8 @@
 
   /**
    * Tests that an exposed taxonomy filter doesn't show unpublished terms.
+   *
+   * @throws \Drupal\Core\Entity\EntityStorageException
    */
   public function testExposedUnpublishedFilterOptions() {
     $this->terms[1][0]->setUnpublished()->save();