diff --git a/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.theme b/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.theme
deleted file mode 100644
index 9802894955f4602f3f1268db87bb7037355ea554..0000000000000000000000000000000000000000
--- a/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.theme
+++ /dev/null
@@ -1,44 +0,0 @@
-<?php
-
-/**
- * @file
- * Theme to test functionality of legacy theme functions.
- *
- * @todo Remove in https://www.drupal.org/project/drupal/issues/3097889
- */
-
-/**
- * Tests a theme overriding a suggestion of a base theme hook.
- */
-function test_legacy_theme_theme_test_preprocess_suggestions__kitten__meerkat($variables) {
-  return 'Theme hook implementor=test_theme_theme_test__suggestion(). Foo=' . $variables['foo'];
-}
-
-/**
- * Implements hook_theme_suggestions_HOOK_alter().
- */
-function test_legacy_theme_theme_suggestions_theme_test_function_suggestions_alter(array &$suggestions, array $variables) {
-  // Theme alter hooks run after module alter hooks, so add this theme
-  // suggestion to the beginning of the array so that the suggestion added by
-  // the theme_suggestions_test module can be picked up when that module is
-  // enabled.
-  array_unshift($suggestions, 'theme_test_function_suggestions__' . 'theme_override');
-}
-
-/**
- * Returns HTML for a theme function suggestion test.
- *
- * Implements the theme_test_function_suggestions__theme_override suggestion.
- */
-function test_legacy_theme_theme_test_function_suggestions__theme_override($variables) {
-  return 'Theme function overridden based on new theme suggestion provided by the test_legacy_theme theme.';
-}
-
-/**
- * Returns HTML for a theme function suggestion test.
- *
- * Implements the theme_test_function_suggestions__module_override suggestion.
- */
-function test_legacy_theme_theme_test_function_suggestions__module_override($variables) {
-  return 'Theme function overridden based on new theme suggestion provided by a module.';
-}
diff --git a/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.info.yml b/core/modules/system/tests/themes/test_theme_with_deprecated_libraries/test_theme_with_deprecated_libraries.info.yml
similarity index 59%
rename from core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.info.yml
rename to core/modules/system/tests/themes/test_theme_with_deprecated_libraries/test_theme_with_deprecated_libraries.info.yml
index 6760629ce6139d4e1dd640b4193ec0dd6efe8c84..0de269b858c842f9656292a1a58be0522a986730 100644
--- a/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.info.yml
+++ b/core/modules/system/tests/themes/test_theme_with_deprecated_libraries/test_theme_with_deprecated_libraries.info.yml
@@ -1,6 +1,6 @@
-name: 'Test legacy theme'
+name: 'Test theme with deprecated libraries'
 type: theme
-description: 'Test theme to test deprecated functionality.'
+description: 'Test theme to test themes with deprecated libraries.'
 version: VERSION
 package: Testing
 base theme: test_theme
@@ -13,4 +13,4 @@ libraries-override:
 
 libraries-extend:
   theme_test/another_deprecated_library:
-    - test_legacy_theme/library
+    - test_theme_with_deprecated_libraries/library
diff --git a/core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.libraries.yml b/core/modules/system/tests/themes/test_theme_with_deprecated_libraries/test_theme_with_deprecated_libraries.libraries.yml
similarity index 100%
rename from core/modules/system/tests/themes/test_legacy_theme/test_legacy_theme.libraries.yml
rename to core/modules/system/tests/themes/test_theme_with_deprecated_libraries/test_theme_with_deprecated_libraries.libraries.yml
diff --git a/core/tests/Drupal/KernelTests/Core/Asset/LibraryDiscoveryIntegrationTest.php b/core/tests/Drupal/KernelTests/Core/Asset/LibraryDiscoveryIntegrationTest.php
index d6afcbea5fe238f1dab30cdd6401153fd0063d0d..4403e73fe87be0d369f39e39aa1cb73476dd146d 100644
--- a/core/tests/Drupal/KernelTests/Core/Asset/LibraryDiscoveryIntegrationTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Asset/LibraryDiscoveryIntegrationTest.php
@@ -238,7 +238,7 @@ public function testDeprecatedLibrary() {
     $this->expectDeprecation('Theme "theme_test" is extending a deprecated library. The "theme_test/another_deprecated_library" asset library is deprecated in drupal:X.0.0 and is removed from drupal:Y.0.0. Use another library instead. See https://www.example.com');
     $this->expectDeprecation('The "theme_test/deprecated_library" asset library is deprecated in drupal:X.0.0 and is removed from drupal:Y.0.0. Use another library instead. See https://www.example.com');
     $this->expectDeprecation('The "theme_test/another_deprecated_library" asset library is deprecated in drupal:X.0.0 and is removed from drupal:Y.0.0. Use another library instead. See https://www.example.com');
-    $this->activateTheme('test_legacy_theme');
+    $this->activateTheme('test_theme_with_deprecated_libraries');
     $this->libraryDiscovery->getLibraryByName('theme_test', 'deprecated_library');
     $this->libraryDiscovery->getLibraryByName('theme_test', 'another_deprecated_library');
   }