diff -u b/core/modules/user/src/Form/UserPermissionsForm.php b/core/modules/user/src/Form/UserPermissionsForm.php
--- b/core/modules/user/src/Form/UserPermissionsForm.php
+++ b/core/modules/user/src/Form/UserPermissionsForm.php
@@ -118,14 +118,14 @@
 
     $form['filters']['text'] = [
       '#type' => 'search',
-      '#title' => $this->t('Search'),
+      '#title' => $this->t('Filter permissions'),
       '#size' => 30,
-      '#placeholder' => $this->t('Enter permission name'),
+      '#placeholder' => $this->t('Filter by name'),
+      '#description' => $this->t('Enter a part of the permission name'),
       '#attributes' => [
         'class' => ['table-filter-text'],
         'data-table' => '#permissions',
         'autocomplete' => 'off',
-        'title' => $this->t('Enter a part of the permission name to filter by.'),
       ],
     ];
 
diff -u b/core/modules/user/user.permissions.js b/core/modules/user/user.permissions.js
--- b/core/modules/user/user.permissions.js
+++ b/core/modules/user/user.permissions.js
@@ -33,7 +33,9 @@
 
       var $input = $('input.table-filter-text').once('table-filter-text');
       var $table = $($input.attr('data-table'));
-      var $rowsAndDetails, $rows, $details;
+      var $rowsAndDetails = void 0;
+      var $rows = void 0;
+      var $details = void 0;
       var searching = false;
 
       function filterPermissionList(e) {
@@ -45,31 +47,21 @@
           var textMatch = $sources.text().toLowerCase().indexOf(query) !== -1;
           $row.closest('tr').toggle(textMatch);
         }
-        // Search over all rows and packages.
+
         $rowsAndDetails.show();
 
-        // Filter if the length of the query is at least 2 characters.
         if (query.length >= 2) {
           searching = true;
           $rows.each(showPermissionRow);
 
-          // Note that we first open all <details> to be able to use ':visible'.
-          // Mark the <details> elements that were closed before filtering, so
-          // they can be reclosed when filtering is removed.
           $details.not('[open]').attr('data-drupal-system-state', 'forced-open');
 
-          // Hide the package <details> if they don't have any visible rows.
-          // Note that we first show() all <details> to be able to use ':visible'.
           $details.attr('open', true).each(hidePackageDetails);
-        }
-        else if (searching) {
+        } else if (searching) {
           searching = false;
           $rowsAndDetails.show();
-          // Return <details> elements that had been closed before filtering
-          // to a closed state.
-          $details.filter('[data-drupal-system-state="forced-open"]')
-            .removeAttr('data-drupal-system-state')
-            .attr('open', false);
+
+          $details.filter('[data-drupal-system-state="forced-open"]').removeAttr('data-drupal-system-state').attr('open', false);
         }
       }
 
@@ -95 +87 @@
-})(jQuery, Drupal);
+})(jQuery, Drupal);
\ No newline at end of file
only in patch2:
unchanged:
--- a/core/modules/user/user.permissions.es6.js
+++ b/core/modules/user/user.permissions.es6.js
@@ -68,6 +68,65 @@
           // Re-insert the table into the DOM.
           $ancestor[method]($table);
         });
+
+      const $input = $('input.table-filter-text').once('table-filter-text');
+      const $table = $($input.attr('data-table'));
+      let $rowsAndDetails;
+      let $rows;
+      let $details;
+      let searching = false;
+
+      function filterPermissionList(e) {
+        const query = $(e.target)
+          .val()
+          .toLowerCase();
+
+        function showPermissionRow(index, row) {
+          const $row = $(row);
+          const $sources = $row.find('.table-filter-text-source');
+          const textMatch =
+            $sources
+              .text()
+              .toLowerCase()
+              .indexOf(query) !== -1;
+          $row.closest('tr').toggle(textMatch);
+        }
+        // Search over all rows and packages.
+        $rowsAndDetails.show();
+
+        // Filter if the length of the query is at least 2 characters.
+        if (query.length >= 2) {
+          searching = true;
+          $rows.each(showPermissionRow);
+
+          // Note that we first open all <details> to be able to use ':visible'.
+          // Mark the <details> elements that were closed before filtering, so
+          // they can be closed again when filtering is removed.
+          $details
+            .not('[open]')
+            .attr('data-drupal-system-state', 'forced-open');
+
+          // Hide the package <details> if they don't have any visible rows.
+          // Note that we first show() all <details> to be able to use ':visible'.
+          $details.attr('open', true).each(hidePackageDetails);
+        } else if (searching) {
+          searching = false;
+          $rowsAndDetails.show();
+          // Return <details> elements that had been closed before filtering
+          // to a closed state.
+          $details
+            .filter('[data-drupal-system-state="forced-open"]')
+            .removeAttr('data-drupal-system-state')
+            .attr('open', false);
+        }
+      }
+
+      if ($table.length) {
+        $rowsAndDetails = $table.find('tr, details');
+        $rows = $table.find('tbody tr');
+        $details = $rowsAndDetails.filter('.package-listing');
+        $input.on('keyup', filterPermissionList);
+      }
     },
 
     /**