Jess
--- a/core/lib/Drupal/Core/Render/Element/ImageButton.php
+++ b/core/lib/Drupal/Core/Render/Element/ImageButton.php
        $input = $form_state->getUserInput();
        foreach (explode('[', $element['#name']) as $element_name) {
          // chop off the ] that may exist.
-          if (substr($element_name, -1) == ']') {
+          if (str_ends_with($element_name, ']')) {
--- a/core/modules/update/tests/src/Functional/UpdateContribTest.php
+++ b/core/modules/update/tests/src/Functional/UpdateContribTest.php
    // Make sure all the update_test_* themes are disabled.
    $extension_config = $this->config('core.extension');
    foreach ($extension_config->get('theme') as $theme => $weight) {
-      if (preg_match('/^update_test_/', $theme)) {
+      if (str_starts_with($theme, 'update_test_')) {