diff --git a/core/misc/cspell/dictionary.txt b/core/misc/cspell/dictionary.txt
index d84d2d7302014d5a44659ebe00928f27d09ea04b..6214b875c42d4d14ab43c617aea0a5debb1415b6 100644
--- a/core/misc/cspell/dictionary.txt
+++ b/core/misc/cspell/dictionary.txt
@@ -161,7 +161,6 @@ classtype
 cldr
 clearfix
 clicksorter
-clist
 closethick
 cnenzrgre
 codesniffer
@@ -824,7 +823,6 @@ sloopal
 smacss
 smalldatetime
 somecompany
-somelinks
 sortablejs
 sourceediting
 spacebar
@@ -921,7 +919,6 @@ tcomment
 templating
 tercera
 testajax
-testattribute
 testblock
 testbody
 testbot
diff --git a/core/modules/filter/tests/src/Functional/FilterHtmlImageSecureTest.php b/core/modules/filter/tests/src/Functional/FilterHtmlImageSecureTest.php
index 3aa0428cfe214b47a193f87d174b25db881bac30..09197673639138400cd3bf220f07238057fed972 100644
--- a/core/modules/filter/tests/src/Functional/FilterHtmlImageSecureTest.php
+++ b/core/modules/filter/tests/src/Functional/FilterHtmlImageSecureTest.php
@@ -45,7 +45,7 @@ protected function setUp(): void {
         'filter_html' => [
           'status' => 1,
           'settings' => [
-            'allowed_html' => '<img src testattribute> <a>',
+            'allowed_html' => '<img src test-attribute> <a>',
           ],
         ],
         'filter_autop' => [
@@ -134,7 +134,7 @@ public function testImageSource() {
       $comment[] = $image . ':';
       // Hash the image source in a custom test attribute, because it might
       // contain characters that confuse XPath.
-      $comment[] = '<img src="' . $image . '" testattribute="' . hash('sha256', $image) . '" />';
+      $comment[] = '<img src="' . $image . '" test-attribute="' . hash('sha256', $image) . '" />';
     }
     $edit = [
       'comment_body[0][value]' => implode("\n", $comment),
@@ -143,7 +143,7 @@ public function testImageSource() {
     $this->submitForm($edit, 'Save');
     foreach ($images as $image => $converted) {
       $found = FALSE;
-      foreach ($this->xpath('//img[@testattribute="' . hash('sha256', $image) . '"]') as $element) {
+      foreach ($this->xpath('//img[@test-attribute="' . hash('sha256', $image) . '"]') as $element) {
         $found = TRUE;
         if ($converted == $red_x_image) {
           $this->assertEquals($red_x_image, $element->getAttribute('src'));
diff --git a/core/modules/system/tests/src/Kernel/Theme/FunctionsTest.php b/core/modules/system/tests/src/Kernel/Theme/FunctionsTest.php
index 2936c3ca79fd2e79504ca30fa2df1da29039495d..1d8824bdbb5fad18ee4c6c31c7acf89cdbcdab84 100644
--- a/core/modules/system/tests/src/Kernel/Theme/FunctionsTest.php
+++ b/core/modules/system/tests/src/Kernel/Theme/FunctionsTest.php
@@ -119,7 +119,7 @@ public function testItemList() {
       [
         '#markup' => 'c',
         'child_list' => [
-          '#attributes' => ['id' => 'clist'],
+          '#attributes' => ['id' => 'c-list'],
           'ca',
           [
             '#markup' => 'cb',
@@ -155,7 +155,7 @@ public function testItemList() {
     $inner_cb .= '<li>cbb</li>';
     $inner_cb .= '</ul></div>';
 
-    $inner_c = '<div class="item-list"><ul id="clist">';
+    $inner_c = '<div class="item-list"><ul id="c-list">';
     $inner_c .= '<li>ca</li>';
     $inner_c .= '<li class="item-class-cb">cb' . $inner_cb . '</li>';
     $inner_c .= '<li>cc</li>';
@@ -196,7 +196,7 @@ public function testLinks() {
 
     // Verify that a list of links is properly rendered.
     $variables = [];
-    $variables['attributes'] = ['id' => 'somelinks'];
+    $variables['attributes'] = ['id' => 'some_links'];
     $variables['links'] = [
       'a link' => [
         'title' => 'A <link>',
@@ -226,7 +226,7 @@ public function testLinks() {
     ];
 
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li>' . Html::escape('Plain "text"') . '</li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
@@ -266,7 +266,7 @@ public function testLinks() {
       'class' => ['a/class'],
     ];
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
@@ -282,7 +282,7 @@ public function testLinks() {
     \Drupal::currentUser()->setAccount(new UserSession(['uid' => 1]));
     $variables['set_active_class'] = TRUE;
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
@@ -317,7 +317,7 @@ public function testIndexedKeyedLinks() {
 
     // Verify that a list of links is properly rendered.
     $variables = [];
-    $variables['attributes'] = ['id' => 'somelinks'];
+    $variables['attributes'] = ['id' => 'some_links'];
     $variables['links'] = [
       [
         'title' => 'A <link>',
@@ -347,7 +347,7 @@ public function testIndexedKeyedLinks() {
     ];
 
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li>' . Html::escape('Plain "text"') . '</li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
@@ -387,7 +387,7 @@ public function testIndexedKeyedLinks() {
       'class' => ['a/class'],
     ];
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
@@ -403,7 +403,7 @@ public function testIndexedKeyedLinks() {
     \Drupal::currentUser()->setAccount(new UserSession(['uid' => 1]));
     $variables['set_active_class'] = TRUE;
     $expected_links = '';
-    $expected_links .= '<ul id="somelinks">';
+    $expected_links .= '<ul id="some_links">';
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';