diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index 4dba53e..bace22d 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -879,7 +879,7 @@
       // called with a context object that includes top-level text nodes.
       // However, to give developers full control of the HTML appearing in the
       // page, and to enable Ajax content to be inserted in places where DIV
-      // elements are not allowed (e.g., within TABLE, TR, and SPAN parents),
+      // elements are not allowed (e.g., within <table>, <tr>, and <span> parents),
       // we check if the new content satisfies the requirement of a single
       // top-level element, and only use the container DIV created above when
       // it doesn't. For more information, please see
diff --git a/core/misc/tableselect.js b/core/misc/tableselect.js
index 8a77695..9a3cc13 100644
--- a/core/misc/tableselect.js
+++ b/core/misc/tableselect.js
@@ -89,7 +89,7 @@
       // range. Also make sure that we are actually checking checkboxes
       // over a range and that a checkbox has been checked or unchecked before.
       if (e.shiftKey && lastChecked && lastChecked !== e.target) {
-        // We use the checkbox's parent TR to do our range searching.
+        // We use the checkbox's parent <tr> to do our range searching.
         Drupal.tableSelectRange($(e.target).closest('tr')[0], $(lastChecked).closest('tr')[0], e.target.checked);
       }
 
diff --git a/core/modules/system/templates/table.html.twig b/core/modules/system/templates/table.html.twig
index f6b32e4..e13edbd 100644
--- a/core/modules/system/templates/table.html.twig
+++ b/core/modules/system/templates/table.html.twig
@@ -12,7 +12,7 @@
  *     https://www.drupal.org/node/893530 and
  *     http://api.drupal.org/api/drupal/includes!theme.inc/function/theme_table/7#comment-5109.
  * - header: Table header cells. Each cell contains the following properties:
- *   - tag: The HTML tag name to use; either TH or TD.
+ *   - tag: The HTML tag name to use; either 'th' or 'td' for a <th> or <td> cell respectively.
  *   - attributes: HTML attributes to apply to the tag.
  *   - content: A localized string for the title of the column.
  *   - field: Field name (required for column sorting).
@@ -24,7 +24,7 @@
  *   - no_striping: A flag indicating that the row should receive no
  *     'even / odd' styling. Defaults to FALSE.
  *   - cells: Table cells of the row. Each cell contains the following keys:
- *     - tag: The HTML tag name to use; either TH or TD.
+ *     - tag: The HTML tag name to use; either 'th' or 'td' for a <th> or <td> cell respectively.
  *     - attributes: Any HTML attributes, such as "colspan", to apply to the
  *       table cell.
  *     - content: The string to display in the table cell.
diff --git a/core/themes/classy/templates/dataset/table.html.twig b/core/themes/classy/templates/dataset/table.html.twig
index 70801d6..aa47e72 100644
--- a/core/themes/classy/templates/dataset/table.html.twig
+++ b/core/themes/classy/templates/dataset/table.html.twig
@@ -12,7 +12,7 @@
  *     https://www.drupal.org/node/893530 and
  *     http://api.drupal.org/api/drupal/includes!theme.inc/function/theme_table/7#comment-5109.
  * - header: Table header cells. Each cell contains the following properties:
- *   - tag: The HTML tag name to use; either TH or TD.
+ *   - tag: The HTML tag name to use; either 'th' or 'td' for a <th> or <td> cell respectively.
  *   - attributes: HTML attributes to apply to the tag.
  *   - content: A localized string for the title of the column.
  *   - field: Field name (required for column sorting).
@@ -24,7 +24,7 @@
  *   - no_striping: A flag indicating that the row should receive no
  *     'even / odd' styling. Defaults to FALSE.
  *   - cells: Table cells of the row. Each cell contains the following keys:
- *     - tag: The HTML tag name to use; either TH or TD.
+ *     - tag: The HTML tag name to use; either 'th' or 'td' for a <th> or <td> cell respectively.
  *     - attributes: Any HTML attributes, such as "colspan", to apply to the
  *       table cell.
  *     - content: The string to display in the table cell.
diff --git a/core/themes/classy/templates/form/fieldset.html.twig b/core/themes/classy/templates/form/fieldset.html.twig
index 4bd7d0a..0d089ed 100644
--- a/core/themes/classy/templates/form/fieldset.html.twig
+++ b/core/themes/classy/templates/form/fieldset.html.twig
@@ -36,7 +36,7 @@
       required ? 'form-required',
     ]
   %}
-  {#  Always wrap fieldset legends in a SPAN for CSS positioning. #}
+  {#  Always wrap fieldset legends in a <span> for CSS positioning. #}
   <legend{{ legend.attributes }}>
     <span{{ legend_span.attributes.addClass(legend_span_classes) }}>{{ legend.title }}</span>
   </legend>
diff --git a/core/themes/seven/css/components/tables.css b/core/themes/seven/css/components/tables.css
index afc9301..bd620ea 100644
--- a/core/themes/seven/css/components/tables.css
+++ b/core/themes/seven/css/components/tables.css
@@ -112,7 +112,7 @@ td.is-active {
   background: none;
 }
 
-/* Force browsers to calculate the width of a 'select all' TH element. */
+/* Force browsers to calculate the width of a 'select all' <th> element. */
 th.select-all {
   width: 1px;
 }