diff --git a/core/modules/block/tests/src/Kernel/BlockValidationTest.php b/core/modules/block/tests/src/Kernel/BlockValidationTest.php
index 7e3e2f234f97575d74f90e12ffadb904d3023cb3..c6571bbc29ece8a8d04fc0883962b52867bf9f22 100644
--- a/core/modules/block/tests/src/Kernel/BlockValidationTest.php
+++ b/core/modules/block/tests/src/Kernel/BlockValidationTest.php
@@ -12,6 +12,7 @@
  * Tests validation of block entities.
  *
  * @group block
+ * @group #slow
  */
 class BlockValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/block_content/tests/src/Kernel/BlockContentAccessHandlerTest.php b/core/modules/block_content/tests/src/Kernel/BlockContentAccessHandlerTest.php
index 6252aa73615653441aa25dc1e6a0c567b91f5f3e..893ae0c73a709f21b64bb913e7ea8068e2859548 100644
--- a/core/modules/block_content/tests/src/Kernel/BlockContentAccessHandlerTest.php
+++ b/core/modules/block_content/tests/src/Kernel/BlockContentAccessHandlerTest.php
@@ -23,6 +23,7 @@
  * @coversDefaultClass \Drupal\block_content\BlockContentAccessControlHandler
  *
  * @group block_content
+ * @group #slow
  */
 class BlockContentAccessHandlerTest extends KernelTestBase {
 
diff --git a/core/modules/block_content/tests/src/Kernel/BlockContentTypeValidationTest.php b/core/modules/block_content/tests/src/Kernel/BlockContentTypeValidationTest.php
index 988064f4492ee6f18a7dfa2468b85728e1cb47dd..1a61c184f74ebb16dafe84fe7c9e0a7ca61da982 100644
--- a/core/modules/block_content/tests/src/Kernel/BlockContentTypeValidationTest.php
+++ b/core/modules/block_content/tests/src/Kernel/BlockContentTypeValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of block_content_type entities.
  *
  * @group block_content
+ * @group #slow
  */
 class BlockContentTypeValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/comment/tests/src/Kernel/Plugin/migrate/source/CommentTypeRequirementsTest.php b/core/modules/comment/tests/src/Kernel/Plugin/migrate/source/CommentTypeRequirementsTest.php
index 379e51803b058b1398cb31e44f516195f7ec6506..c04c478f3a2f35417ac4f94057a0e116a0b2a82b 100644
--- a/core/modules/comment/tests/src/Kernel/Plugin/migrate/source/CommentTypeRequirementsTest.php
+++ b/core/modules/comment/tests/src/Kernel/Plugin/migrate/source/CommentTypeRequirementsTest.php
@@ -11,6 +11,7 @@
  * Tests check requirements for comment type source plugin.
  *
  * @group comment
+ * @group #slow
  */
 class CommentTypeRequirementsTest extends MigrateDrupal7TestBase {
 
diff --git a/core/modules/contact/tests/src/Kernel/ContactFormValidationTest.php b/core/modules/contact/tests/src/Kernel/ContactFormValidationTest.php
index 71fe9aae9531c81996a89aadc5a82e0ac7e0b3a7..a79a9b2b84b682f6fdff23f39ad5f111e1772314 100644
--- a/core/modules/contact/tests/src/Kernel/ContactFormValidationTest.php
+++ b/core/modules/contact/tests/src/Kernel/ContactFormValidationTest.php
@@ -12,6 +12,7 @@
  * Tests validation of contact_form entities.
  *
  * @group contact
+ * @group #slow
  */
 class ContactFormValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/content_moderation/tests/src/Kernel/ModerationStateFieldItemListTest.php b/core/modules/content_moderation/tests/src/Kernel/ModerationStateFieldItemListTest.php
index 1c83da34b6975d64867dbccc5f17f5ac5d44daea..249418a2c32c30b49894c5330c418e256594d97e 100644
--- a/core/modules/content_moderation/tests/src/Kernel/ModerationStateFieldItemListTest.php
+++ b/core/modules/content_moderation/tests/src/Kernel/ModerationStateFieldItemListTest.php
@@ -16,6 +16,7 @@
  * @coversDefaultClass \Drupal\content_moderation\Plugin\Field\ModerationStateFieldItemList
  *
  * @group content_moderation
+ * @group #slow
  */
 class ModerationStateFieldItemListTest extends KernelTestBase {
 
diff --git a/core/modules/editor/tests/src/Kernel/EditorValidationTest.php b/core/modules/editor/tests/src/Kernel/EditorValidationTest.php
index 956177d94a1fda53f6091cb5ac9f87a462c1c644..cf45fb8a4143a0d08414c19f91ccdd6043aa8200 100644
--- a/core/modules/editor/tests/src/Kernel/EditorValidationTest.php
+++ b/core/modules/editor/tests/src/Kernel/EditorValidationTest.php
@@ -13,6 +13,7 @@
  * Tests validation of editor entities.
  *
  * @group editor
+ * @group #slow
  */
 class EditorValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/filter/tests/src/Kernel/FilterFormatValidationTest.php b/core/modules/filter/tests/src/Kernel/FilterFormatValidationTest.php
index 5fd481e5bcfc072879c60e370d5eaf4ee24a6437..03241f26f2bbbfc09c3d4b88c25210cf9bdabeed 100644
--- a/core/modules/filter/tests/src/Kernel/FilterFormatValidationTest.php
+++ b/core/modules/filter/tests/src/Kernel/FilterFormatValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of filter_format entities.
  *
  * @group filter
+ * @group #slow
  */
 class FilterFormatValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/locale/tests/src/Kernel/LocaleConfigSubscriberForeignTest.php b/core/modules/locale/tests/src/Kernel/LocaleConfigSubscriberForeignTest.php
index 8648ca59f70706374f29cc1043fb9fd55341d15e..c15cc884a04d348e9fa82ad23900cd59f99548c0 100644
--- a/core/modules/locale/tests/src/Kernel/LocaleConfigSubscriberForeignTest.php
+++ b/core/modules/locale/tests/src/Kernel/LocaleConfigSubscriberForeignTest.php
@@ -12,6 +12,7 @@
  * Tests default configuration handling with a foreign default language.
  *
  * @group locale
+ * @group #slow
  */
 class LocaleConfigSubscriberForeignTest extends LocaleConfigSubscriberTest {
 
diff --git a/core/modules/media/tests/src/Kernel/MediaEmbedFilterTest.php b/core/modules/media/tests/src/Kernel/MediaEmbedFilterTest.php
index e283aae92bb1bb8eb2bda4d2f7631d59903cf984..f67c940c6d387d36cb5f22369f8c952dbf0732d2 100644
--- a/core/modules/media/tests/src/Kernel/MediaEmbedFilterTest.php
+++ b/core/modules/media/tests/src/Kernel/MediaEmbedFilterTest.php
@@ -12,6 +12,7 @@
 /**
  * @coversDefaultClass \Drupal\media\Plugin\Filter\MediaEmbed
  * @group media
+ * @group #slow
  */
 class MediaEmbedFilterTest extends MediaEmbedFilterTestBase {
 
diff --git a/core/modules/media/tests/src/Kernel/MediaTypeValidationTest.php b/core/modules/media/tests/src/Kernel/MediaTypeValidationTest.php
index 43be795011feb1a91830a3a2a6de91243099a12a..1b070de3517cc934754081e4e0e9edd3ba1ae7b6 100644
--- a/core/modules/media/tests/src/Kernel/MediaTypeValidationTest.php
+++ b/core/modules/media/tests/src/Kernel/MediaTypeValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of media_type entities.
  *
  * @group media
+ * @group #slow
  */
 class MediaTypeValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/media_library/tests/src/Kernel/MediaLibraryStateTest.php b/core/modules/media_library/tests/src/Kernel/MediaLibraryStateTest.php
index a861d5348924b6ea92dce408b077a0eb661a3ed1..3256e914cd251dd2ae3b0f2c574ec73a8beb13c4 100644
--- a/core/modules/media_library/tests/src/Kernel/MediaLibraryStateTest.php
+++ b/core/modules/media_library/tests/src/Kernel/MediaLibraryStateTest.php
@@ -16,6 +16,7 @@
  * Tests the media library state value object.
  *
  * @group media_library
+ * @group #slow
  *
  * @coversDefaultClass \Drupal\media_library\MediaLibraryState
  */
diff --git a/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/ContentEntityTest.php b/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/ContentEntityTest.php
index c4cdaa3596b633adade1091e1f4af94df1988232..84d43a6d00132de1a61b77f4a140c39d50383640 100644
--- a/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/ContentEntityTest.php
+++ b/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/ContentEntityTest.php
@@ -24,6 +24,7 @@
  * Tests the entity content source plugin.
  *
  * @group migrate_drupal
+ * @group #slow
  */
 class ContentEntityTest extends KernelTestBase {
 
diff --git a/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/VariableTest.php b/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/VariableTest.php
index ac17c700bcb91580355f7e7b24ab1d71a1edb144..590fd1b447d9dda4d05085eecff0c33fd4d2633e 100644
--- a/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/VariableTest.php
+++ b/core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/source/VariableTest.php
@@ -12,6 +12,7 @@
  * @covers \Drupal\migrate_drupal\Plugin\migrate\source\Variable
  *
  * @group migrate_drupal
+ * @group #slow
  */
 class VariableTest extends MigrateSqlSourceTestBase {
 
diff --git a/core/modules/node/tests/src/Kernel/NodeTypeValidationTest.php b/core/modules/node/tests/src/Kernel/NodeTypeValidationTest.php
index c8c4a22058d13af89a047d59401b74af94440be4..1500df272b3ef017af841aee601a2056a1c4d831 100644
--- a/core/modules/node/tests/src/Kernel/NodeTypeValidationTest.php
+++ b/core/modules/node/tests/src/Kernel/NodeTypeValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of node_type entities.
  *
  * @group node
+ * @group #slow
  */
 class NodeTypeValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/responsive_image/tests/src/Kernel/ResponsiveImageStyleValidationTest.php b/core/modules/responsive_image/tests/src/Kernel/ResponsiveImageStyleValidationTest.php
index 6ba1184a41cbae0f0c7fa641b6314767c976997e..fe0e0cf5f1bf9a10a0f859c187b78b37011a3f7a 100644
--- a/core/modules/responsive_image/tests/src/Kernel/ResponsiveImageStyleValidationTest.php
+++ b/core/modules/responsive_image/tests/src/Kernel/ResponsiveImageStyleValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of responsive_image_style entities.
  *
  * @group responsive_image
+ * @group #slow
  */
 class ResponsiveImageStyleValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/rest/tests/src/Kernel/Entity/RestResourceConfigValidationTest.php b/core/modules/rest/tests/src/Kernel/Entity/RestResourceConfigValidationTest.php
index 56e423b3fe38294499bc7286b0b492484ff95484..673003d51aec7179c2bf37c69b0cfd3f86cf2576 100644
--- a/core/modules/rest/tests/src/Kernel/Entity/RestResourceConfigValidationTest.php
+++ b/core/modules/rest/tests/src/Kernel/Entity/RestResourceConfigValidationTest.php
@@ -12,6 +12,7 @@
  * Tests validation of rest_resource_config entities.
  *
  * @group rest
+ * @group #slow
  */
 class RestResourceConfigValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/search/tests/src/Kernel/SearchPageValidationTest.php b/core/modules/search/tests/src/Kernel/SearchPageValidationTest.php
index 8bb2a96b1650bd9aa2acd20f3c5823460cfc9136..9a9a514d5c50ebdcde22a6a48bb23e0ad4b9df4d 100644
--- a/core/modules/search/tests/src/Kernel/SearchPageValidationTest.php
+++ b/core/modules/search/tests/src/Kernel/SearchPageValidationTest.php
@@ -13,6 +13,7 @@
  * Tests validation of search_page entities.
  *
  * @group search
+ * @group #slow
  */
 class SearchPageValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/shortcut/tests/src/Kernel/ShortcutSetValidationTest.php b/core/modules/shortcut/tests/src/Kernel/ShortcutSetValidationTest.php
index f61b03aff6c3e5283f66b4399fb77c9146604206..6976a76b4086d4211a4f8ddeaca8f2ea9ada25f9 100644
--- a/core/modules/shortcut/tests/src/Kernel/ShortcutSetValidationTest.php
+++ b/core/modules/shortcut/tests/src/Kernel/ShortcutSetValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of shortcut_set entities.
  *
  * @group shortcut
+ * @group #slow
  */
 class ShortcutSetValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/system/tests/src/Kernel/Entity/ActionValidationTest.php b/core/modules/system/tests/src/Kernel/Entity/ActionValidationTest.php
index 7da634cf377f8a139b4fdb6c7733b8f49090c8d8..f54f9a1eb9df213c5aa03b44be946c00efcb504a 100644
--- a/core/modules/system/tests/src/Kernel/Entity/ActionValidationTest.php
+++ b/core/modules/system/tests/src/Kernel/Entity/ActionValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of action entities.
  *
  * @group system
+ * @group #slow
  */
 class ActionValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/system/tests/src/Kernel/Entity/MenuValidationTest.php b/core/modules/system/tests/src/Kernel/Entity/MenuValidationTest.php
index 906960a0d6838f367fb9111c64973c0e1fb3edab..9dff686d7280514754dc53be03592a4815edbe5c 100644
--- a/core/modules/system/tests/src/Kernel/Entity/MenuValidationTest.php
+++ b/core/modules/system/tests/src/Kernel/Entity/MenuValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of menu entities.
  *
  * @group system
+ * @group #slow
  */
 class MenuValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/modules/user/tests/src/Kernel/RoleValidationTest.php b/core/modules/user/tests/src/Kernel/RoleValidationTest.php
index 6d532e7c72c62b3c0bdd33b8ee775472ad29555d..928928533e66f68e6ede038de37c985b27df34e0 100644
--- a/core/modules/user/tests/src/Kernel/RoleValidationTest.php
+++ b/core/modules/user/tests/src/Kernel/RoleValidationTest.php
@@ -11,6 +11,7 @@
  * Tests validation of user_role entities.
  *
  * @group user
+ * @group #slow
  */
 class RoleValidationTest extends ConfigEntityValidationTestBase {
 
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/FieldableEntityDefinitionUpdateTest.php b/core/tests/Drupal/KernelTests/Core/Entity/FieldableEntityDefinitionUpdateTest.php
index 4a70ae7091c90fb7a4d470161744a2683f9821df..3155142602f377e9cdae6259695fd88e3ef2e80c 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/FieldableEntityDefinitionUpdateTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/FieldableEntityDefinitionUpdateTest.php
@@ -16,6 +16,7 @@
  * @coversDefaultClass \Drupal\Core\Entity\EntityDefinitionUpdateManager
  *
  * @group Entity
+ * @group #slow
  */
 class FieldableEntityDefinitionUpdateTest extends EntityKernelTestBase {
 
diff --git a/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php b/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
index 4bb9c5efa29acadf53aba138f7022e20741cc200..fd79c5b314a2c7fe97a2350a728505597202b9fd 100644
--- a/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Routing/RouteProviderTest.php
@@ -29,6 +29,7 @@
  * Confirm that the default route provider is working correctly.
  *
  * @group Routing
+ * @group #slow
  */
 class RouteProviderTest extends KernelTestBase {
 
diff --git a/core/tests/Drupal/KernelTests/Core/Test/Comparator/MarkupInterfaceComparatorTest.php b/core/tests/Drupal/KernelTests/Core/Test/Comparator/MarkupInterfaceComparatorTest.php
index 8e3a37b8baf3e427c6034dee9b6f4c10c136f0f1..6c43e1911a166a0c0d4f6859b7bd64f5857eb2bc 100644
--- a/core/tests/Drupal/KernelTests/Core/Test/Comparator/MarkupInterfaceComparatorTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Test/Comparator/MarkupInterfaceComparatorTest.php
@@ -18,6 +18,7 @@
  * objects to strings can require an initialized container.
  *
  * @group Test
+ * @group #slow
  *
  * @coversDefaultClass \Drupal\TestTools\Comparator\MarkupInterfaceComparator
  */