diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentJsonAnonTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentJsonAnonTest.php
index 8c54ec12863b93c88bf0bfcb250ab6ed28268872..bacc9149c095ca982507dd4e433bae41442520d3 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentJsonAnonTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentJsonAnonTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentJsonAnonTest extends CommentResourceTestBase {
 
diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentJsonBasicAuthTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentJsonBasicAuthTest.php
index ae1dd425354588c6a5d527d0a2a94f4e1925ad58..e83686afc7b1cb4dcf2c08cfd75ad14fced46afe 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentJsonBasicAuthTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentJsonBasicAuthTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentJsonBasicAuthTest extends CommentResourceTestBase {
 
diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentJsonCookieTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentJsonCookieTest.php
index 846335acc3eb963c42f3d9d0353007c30b0c9cda..5d40b6c6d1c45985f80ed98889b89a9b355f278e 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentJsonCookieTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentJsonCookieTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentJsonCookieTest extends CommentResourceTestBase {
 
diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentXmlAnonTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentXmlAnonTest.php
index 1950cbabf37595f0b363e67f1fde87a0d1f3b654..30027c55bef4c01077674f417673b21266c28d84 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentXmlAnonTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentXmlAnonTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentXmlAnonTest extends CommentResourceTestBase {
 
diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentXmlBasicAuthTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentXmlBasicAuthTest.php
index be155e35cdf976fdbbb34b5d71e3bb1d519627ad..7bd6a42a1e3b4e8dfcadcba7978df9a2830ddac0 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentXmlBasicAuthTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentXmlBasicAuthTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentXmlBasicAuthTest extends CommentResourceTestBase {
 
diff --git a/core/modules/comment/tests/src/Functional/Rest/CommentXmlCookieTest.php b/core/modules/comment/tests/src/Functional/Rest/CommentXmlCookieTest.php
index 57631e1880f1cf3d5c9e8a5a2b3c85401743c4e7..7e3a6134e7d450c394991aecb58a7630a459efa8 100644
--- a/core/modules/comment/tests/src/Functional/Rest/CommentXmlCookieTest.php
+++ b/core/modules/comment/tests/src/Functional/Rest/CommentXmlCookieTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class CommentXmlCookieTest extends CommentResourceTestBase {
 
diff --git a/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
index 250417e11f87fe327901c89433637a4a9acb2a83..4c45d94547388b0418b617cf6ff0c7ba8ee48322 100644
--- a/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
+++ b/core/modules/datetime_range/tests/src/Functional/DateRangeFieldTest.php
@@ -16,6 +16,7 @@
  * Tests Daterange field functionality.
  *
  * @group datetime
+ * @group #slow
  */
 class DateRangeFieldTest extends DateTestBase {
 
diff --git a/core/modules/dblog/tests/src/Functional/DbLogTest.php b/core/modules/dblog/tests/src/Functional/DbLogTest.php
index 73a4e2467b179f9e33cf975511a8dadbc1edc268..b43086ae19bd8424d4f41613a76b129692419f34 100644
--- a/core/modules/dblog/tests/src/Functional/DbLogTest.php
+++ b/core/modules/dblog/tests/src/Functional/DbLogTest.php
@@ -17,6 +17,7 @@
  * Verifies log entries and user access based on permissions.
  *
  * @group dblog
+ * @group #slow
  */
 class DbLogTest extends BrowserTestBase {
   use FakeLogEntries;
diff --git a/core/modules/dblog/tests/src/Functional/DbLogViewsTest.php b/core/modules/dblog/tests/src/Functional/DbLogViewsTest.php
index d6794a01c49b90d7f8fe233ffa560955d7d39421..7d9be811aca5686eab046fee1460a53d5283039d 100644
--- a/core/modules/dblog/tests/src/Functional/DbLogViewsTest.php
+++ b/core/modules/dblog/tests/src/Functional/DbLogViewsTest.php
@@ -10,6 +10,7 @@
  * @see Drupal\dblog\Tests\DbLogTest
  *
  * @group dblog
+ * @group #slow
  */
 class DbLogViewsTest extends DbLogTest {
 
diff --git a/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php b/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
index 54082847b19db0f240ef08c686fd510b20f38212..fa89f441b5b87ba966741cbdc1f5713fe9585c90 100644
--- a/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
+++ b/core/modules/editor/tests/src/Functional/Update/EditorAddLazyLoadImageFilterUpdateTest.php
@@ -10,6 +10,7 @@
  * Tests adding editor_image_lazy_load filter to editor_file_reference.
  *
  * @group Update
+ * @group #slow
  */
 class EditorAddLazyLoadImageFilterUpdateTest extends UpdatePathTestBase {
 
diff --git a/core/modules/file/tests/src/Functional/FileManagedFileElementTest.php b/core/modules/file/tests/src/Functional/FileManagedFileElementTest.php
index 36f2d1e782d2efc2b528be8a7b498c9b04bfe9fe..3c509d000c24c592351cd1b6ee6569971cc855e1 100644
--- a/core/modules/file/tests/src/Functional/FileManagedFileElementTest.php
+++ b/core/modules/file/tests/src/Functional/FileManagedFileElementTest.php
@@ -8,6 +8,7 @@
  * Tests the 'managed_file' element type.
  *
  * @group file
+ * @group #slow
  * @todo Create a FileTestBase class and move FileFieldTestBase methods
  *   that aren't related to fields into it.
  */
diff --git a/core/modules/filter/tests/src/Functional/FilterAdminTest.php b/core/modules/filter/tests/src/Functional/FilterAdminTest.php
index 7d2cf73a046fc8d80388955a7284764102708558..ed2dc4cd2bd358e50a02c65340c6d4fec04cccb8 100644
--- a/core/modules/filter/tests/src/Functional/FilterAdminTest.php
+++ b/core/modules/filter/tests/src/Functional/FilterAdminTest.php
@@ -15,6 +15,7 @@
  * Thoroughly test the administrative interface of the filter module.
  *
  * @group filter
+ * @group #slow
  */
 class FilterAdminTest extends BrowserTestBase {
 
diff --git a/core/modules/help/tests/src/Functional/Update/HelpTopicsMerge.php b/core/modules/help/tests/src/Functional/Update/HelpTopicsMerge.php
index f6a9cfa7c957011311b3108c4796c6f70c8aba3e..80dd75256c07d37d345fdb39cad20ca5baa1d0a0 100644
--- a/core/modules/help/tests/src/Functional/Update/HelpTopicsMerge.php
+++ b/core/modules/help/tests/src/Functional/Update/HelpTopicsMerge.php
@@ -10,6 +10,7 @@
  * Tests merging help topics module when the module is not installed.
  *
  * @group Update
+ * @group #slow
  */
 class HelpTopicsMerge extends UpdatePathTestBase {
 
diff --git a/core/modules/help/tests/src/Functional/Update/HelpTopicsUninstall.php b/core/modules/help/tests/src/Functional/Update/HelpTopicsUninstall.php
index 69ea80b670c21770a53913f3179254059cb70b4c..96d3672e8d7fb08a5d794d67e6826d827444ca47 100644
--- a/core/modules/help/tests/src/Functional/Update/HelpTopicsUninstall.php
+++ b/core/modules/help/tests/src/Functional/Update/HelpTopicsUninstall.php
@@ -8,6 +8,7 @@
  * Tests merging help topics module when the module is enabled.
  *
  * @group Update
+ * @group #slow
  */
 class HelpTopicsUninstall extends UpdatePathTestBase {
 
diff --git a/core/modules/jsonapi/tests/src/Functional/EntityTestComputedFieldTest.php b/core/modules/jsonapi/tests/src/Functional/EntityTestComputedFieldTest.php
index 0f22c1187dd40126b0a5ac7c4516c80f73c73122..36e1b4bf7d4a76c90a0c769b87fc63d960b34c10 100644
--- a/core/modules/jsonapi/tests/src/Functional/EntityTestComputedFieldTest.php
+++ b/core/modules/jsonapi/tests/src/Functional/EntityTestComputedFieldTest.php
@@ -11,6 +11,7 @@
  * JSON:API integration test for the "EntityTestComputedField" content entity type.
  *
  * @group jsonapi
+ * @group #slow
  */
 class EntityTestComputedFieldTest extends ResourceTestBase {
 
diff --git a/core/modules/jsonapi/tests/src/Functional/EntityTestMapFieldTest.php b/core/modules/jsonapi/tests/src/Functional/EntityTestMapFieldTest.php
index 1bb12240520dbc83f89ed414ed6e08592aa57876..8fa9fe4a50561383eb7e6ecb19400bfe7c7a2a4e 100644
--- a/core/modules/jsonapi/tests/src/Functional/EntityTestMapFieldTest.php
+++ b/core/modules/jsonapi/tests/src/Functional/EntityTestMapFieldTest.php
@@ -10,6 +10,7 @@
  * JSON:API integration test for the "EntityTestMapField" content entity type.
  *
  * @group jsonapi
+ * @group #slow
  */
 class EntityTestMapFieldTest extends ResourceTestBase {
 
diff --git a/core/modules/jsonapi/tests/src/Functional/EntityTestTest.php b/core/modules/jsonapi/tests/src/Functional/EntityTestTest.php
index 6e59823b7aa9639bef7921530e5c02fbc57232a8..e4df38e318911daaaa2b4826b46c72426f6c68d5 100644
--- a/core/modules/jsonapi/tests/src/Functional/EntityTestTest.php
+++ b/core/modules/jsonapi/tests/src/Functional/EntityTestTest.php
@@ -12,6 +12,7 @@
  * JSON:API integration test for the "EntityTest" content entity type.
  *
  * @group jsonapi
+ * @group #slow
  */
 class EntityTestTest extends ResourceTestBase {
 
diff --git a/core/modules/jsonapi/tests/src/Functional/ShortcutTest.php b/core/modules/jsonapi/tests/src/Functional/ShortcutTest.php
index c03a78ab651b13e3a6fc8f9a2ad34ca0f6358ac2..5ea7e3aeab908c4560c6f8d590c83d098aafc85f 100644
--- a/core/modules/jsonapi/tests/src/Functional/ShortcutTest.php
+++ b/core/modules/jsonapi/tests/src/Functional/ShortcutTest.php
@@ -15,6 +15,7 @@
  * JSON:API integration test for the "Shortcut" content entity type.
  *
  * @group jsonapi
+ * @group #slow
  */
 class ShortcutTest extends ResourceTestBase {
 
diff --git a/core/modules/jsonapi/tests/src/Functional/TermTest.php b/core/modules/jsonapi/tests/src/Functional/TermTest.php
index 31a1c71ad067064517415436bb90f79aa0e8202c..6cb401ba0f1de9cff0145d47d42df8560febd8f3 100644
--- a/core/modules/jsonapi/tests/src/Functional/TermTest.php
+++ b/core/modules/jsonapi/tests/src/Functional/TermTest.php
@@ -16,6 +16,7 @@
  * JSON:API integration test for the "Term" content entity type.
  *
  * @group jsonapi
+ * @group #slow
  */
 class TermTest extends ResourceTestBase {
 
diff --git a/core/modules/locale/tests/src/Functional/LocaleTranslationUiTest.php b/core/modules/locale/tests/src/Functional/LocaleTranslationUiTest.php
index ced6504a4a6f57be21a73eac6b2d75cab82b06eb..f8369eef726541eac798ff566bb4fb09e351988f 100644
--- a/core/modules/locale/tests/src/Functional/LocaleTranslationUiTest.php
+++ b/core/modules/locale/tests/src/Functional/LocaleTranslationUiTest.php
@@ -13,6 +13,7 @@
  * Tests the validation of translation strings and search results.
  *
  * @group locale
+ * @group #slow
  */
 class LocaleTranslationUiTest extends BrowserTestBase {
 
diff --git a/core/modules/media/tests/src/Functional/MediaAccessTest.php b/core/modules/media/tests/src/Functional/MediaAccessTest.php
index a3ed47efb3580742a0d9fe6a8eaa47ffa2602162..93186afae7dc84905430036c6303ad65a128abe7 100644
--- a/core/modules/media/tests/src/Functional/MediaAccessTest.php
+++ b/core/modules/media/tests/src/Functional/MediaAccessTest.php
@@ -13,6 +13,7 @@
  * Basic access tests for Media.
  *
  * @group media
+ * @group #slow
  */
 class MediaAccessTest extends MediaFunctionalTestBase {
 
diff --git a/core/modules/media/tests/src/Functional/MediaRevisionTest.php b/core/modules/media/tests/src/Functional/MediaRevisionTest.php
index 88c71ce32f2d038f73b0f89a786f53cea03caa03..fbeeff35d1a42be7bec719f445e4e8268a093f82 100644
--- a/core/modules/media/tests/src/Functional/MediaRevisionTest.php
+++ b/core/modules/media/tests/src/Functional/MediaRevisionTest.php
@@ -13,6 +13,7 @@
  * Tests the revisions of media entities.
  *
  * @group media
+ * @group #slow
  */
 class MediaRevisionTest extends MediaFunctionalTestBase {
 
diff --git a/core/modules/menu_ui/tests/src/Functional/MenuUiTest.php b/core/modules/menu_ui/tests/src/Functional/MenuUiTest.php
index 586e545a1888dd4f231c61e38023a09c3fb0e18a..9a92afcf564b9f92343dcb2a5327d5b4aa246568 100644
--- a/core/modules/menu_ui/tests/src/Functional/MenuUiTest.php
+++ b/core/modules/menu_ui/tests/src/Functional/MenuUiTest.php
@@ -21,6 +21,7 @@
  * Tools menu, checks their data, and deletes them using the UI.
  *
  * @group menu_ui
+ * @group #slow
  */
 class MenuUiTest extends BrowserTestBase {
 
diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/SourceProviderTest.php b/core/modules/migrate_drupal_ui/tests/src/Functional/SourceProviderTest.php
index e6768723eb8a36af20fc7edf358b1513c18cf2c2..d70bdb156688c7b22169210f3f53e967c353f164 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/SourceProviderTest.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/SourceProviderTest.php
@@ -6,6 +6,7 @@
  * Tests that a missing source provider error message is displayed.
  *
  * @group migrate_drupal_ui
+ * @group #slow
  */
 class SourceProviderTest extends MigrateUpgradeTestBase {
 
diff --git a/core/modules/node/tests/src/Functional/NodeCreationTest.php b/core/modules/node/tests/src/Functional/NodeCreationTest.php
index fd041cb9bdc3b28ee1adc9ea1e941e754c567e69..60e4e1433352049d5adadcc8946268552e3fb216 100644
--- a/core/modules/node/tests/src/Functional/NodeCreationTest.php
+++ b/core/modules/node/tests/src/Functional/NodeCreationTest.php
@@ -11,6 +11,7 @@
  * Create a node and test saving it.
  *
  * @group node
+ * @group #slow
  */
 class NodeCreationTest extends NodeTestBase {
 
diff --git a/core/modules/node/tests/src/Functional/NodeQueryAlterTest.php b/core/modules/node/tests/src/Functional/NodeQueryAlterTest.php
index 1fb3afd9cb0c5b41f60c4dcf604f1c18613e25be..caf40fb31275fb9f09aab7ff2e3dc9fa83594f76 100644
--- a/core/modules/node/tests/src/Functional/NodeQueryAlterTest.php
+++ b/core/modules/node/tests/src/Functional/NodeQueryAlterTest.php
@@ -9,6 +9,7 @@
  * Tests that node access queries are properly altered by the node module.
  *
  * @group node
+ * @group #slow
  */
 class NodeQueryAlterTest extends NodeTestBase {
 
diff --git a/core/modules/node/tests/src/Functional/NodeTypeTest.php b/core/modules/node/tests/src/Functional/NodeTypeTest.php
index 3601ce25058aff1d831e452a00b2788de5e72f73..e258d89c9c0dc3463ed5f93a71d224631e3b88e9 100644
--- a/core/modules/node/tests/src/Functional/NodeTypeTest.php
+++ b/core/modules/node/tests/src/Functional/NodeTypeTest.php
@@ -12,6 +12,7 @@
  * Ensures that node type functions work correctly.
  *
  * @group node
+ * @group #slow
  */
 class NodeTypeTest extends NodeTestBase {
 
diff --git a/core/modules/options/tests/src/Functional/OptionsFieldUITest.php b/core/modules/options/tests/src/Functional/OptionsFieldUITest.php
index ad83c71e98a4935f185d59cfec65a266bd784db1..d0514eb7ac00576d9676833902f41e2b03241cf7 100644
--- a/core/modules/options/tests/src/Functional/OptionsFieldUITest.php
+++ b/core/modules/options/tests/src/Functional/OptionsFieldUITest.php
@@ -10,6 +10,7 @@
  * Tests the Options field UI functionality.
  *
  * @group options
+ * @group #slow
  */
 class OptionsFieldUITest extends FieldTestBase {
 
diff --git a/core/modules/search/tests/src/Functional/SearchConfigSettingsFormTest.php b/core/modules/search/tests/src/Functional/SearchConfigSettingsFormTest.php
index 8043c8def516717bd2587e96250f9e8de3874558..b5e97d4468a60a286a0ec30c16a98c2810d38cfc 100644
--- a/core/modules/search/tests/src/Functional/SearchConfigSettingsFormTest.php
+++ b/core/modules/search/tests/src/Functional/SearchConfigSettingsFormTest.php
@@ -11,6 +11,7 @@
  * Verify the search config settings form.
  *
  * @group search
+ * @group #slow
  */
 class SearchConfigSettingsFormTest extends BrowserTestBase {
 
diff --git a/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestTextItemNormalizerTest.php b/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestTextItemNormalizerTest.php
index 23bbb6f38ff7056a9ec616d3d8d0b8567a95dc46..8c05ca3897fa9d2cffd55d582fb1f3643cb71df2 100644
--- a/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestTextItemNormalizerTest.php
+++ b/core/modules/system/tests/modules/entity_test/tests/src/Functional/Rest/EntityTestTextItemNormalizerTest.php
@@ -9,6 +9,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class EntityTestTextItemNormalizerTest extends EntityTestResourceTestBase {
 
diff --git a/core/modules/system/tests/src/Functional/Datetime/TimeZoneAbbreviationRouteTest.php b/core/modules/system/tests/src/Functional/Datetime/TimeZoneAbbreviationRouteTest.php
index 1cee7b46bbd19898f42438c6f0f9271259729af3..ab2e482b27f3a7746b8b5e9d001384cf2814b798 100644
--- a/core/modules/system/tests/src/Functional/Datetime/TimeZoneAbbreviationRouteTest.php
+++ b/core/modules/system/tests/src/Functional/Datetime/TimeZoneAbbreviationRouteTest.php
@@ -10,6 +10,7 @@
  * Tests converting JavaScript time zone abbreviations to time zone identifiers.
  *
  * @group Datetime
+ * @group #slow
  */
 class TimeZoneAbbreviationRouteTest extends BrowserTestBase {
 
diff --git a/core/modules/system/tests/src/Functional/Entity/EntityFormTest.php b/core/modules/system/tests/src/Functional/Entity/EntityFormTest.php
index b36fc81680455f9f3d2020d2d64d9835ad8c11a9..cd4f3e4789dd652db1a17a2572cbe8cd7341261a 100644
--- a/core/modules/system/tests/src/Functional/Entity/EntityFormTest.php
+++ b/core/modules/system/tests/src/Functional/Entity/EntityFormTest.php
@@ -12,6 +12,7 @@
  * Tests the entity form.
  *
  * @group Entity
+ * @group #slow
  */
 class EntityFormTest extends BrowserTestBase {
 
diff --git a/core/modules/system/tests/src/Functional/Form/ElementsTableSelectTest.php b/core/modules/system/tests/src/Functional/Form/ElementsTableSelectTest.php
index 98567e2a6022fd4546533e5e1f4c086cbe0e1695..1d1bf1aedfb42d06a0d4d6923454a8677d13113f 100644
--- a/core/modules/system/tests/src/Functional/Form/ElementsTableSelectTest.php
+++ b/core/modules/system/tests/src/Functional/Form/ElementsTableSelectTest.php
@@ -9,6 +9,7 @@
  * Tests the tableselect form element for expected behavior.
  *
  * @group Form
+ * @group #slow
  */
 class ElementsTableSelectTest extends BrowserTestBase {
 
diff --git a/core/modules/system/tests/src/Functional/Update/ConfigSyncReadmeUpdateTest.php b/core/modules/system/tests/src/Functional/Update/ConfigSyncReadmeUpdateTest.php
index 415fd8df7a1f0fc9b41c6219f21ef21113d56130..1ceb8b1bb43db8881b4229c299c917025c92f66b 100644
--- a/core/modules/system/tests/src/Functional/Update/ConfigSyncReadmeUpdateTest.php
+++ b/core/modules/system/tests/src/Functional/Update/ConfigSyncReadmeUpdateTest.php
@@ -9,6 +9,7 @@
  * Tests update to readme inside the configuration synchronization directory.
  *
  * @group Update
+ * @group #slow
  */
 class ConfigSyncReadmeUpdateTest extends UpdatePathTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserJsonAnonTest.php b/core/modules/user/tests/src/Functional/Rest/UserJsonAnonTest.php
index ba2b0b392d8e4219c0559513713d84c60ef5d3e3..accbd7065a430bc9ffd08f332c149f584265095e 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserJsonAnonTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserJsonAnonTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserJsonAnonTest extends UserResourceTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserJsonBasicAuthTest.php b/core/modules/user/tests/src/Functional/Rest/UserJsonBasicAuthTest.php
index 169da9e952c9ebc53c6b1cdd2189d75ac454b0f1..353cd71863a6886c377d8e8034ea91aef233eb86 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserJsonBasicAuthTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserJsonBasicAuthTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserJsonBasicAuthTest extends UserResourceTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php b/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php
index 21a46cd06fd90159d385691e583f9ed0e325c24c..741d33cfad52d58ddff487f64e980db3d21b9457 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserJsonCookieTest.php
@@ -6,6 +6,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserJsonCookieTest extends UserResourceTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserXmlAnonTest.php b/core/modules/user/tests/src/Functional/Rest/UserXmlAnonTest.php
index 3340729364aec1dc9f2ea1529e8c76a2e95e0623..cfaded78ec9607b0f857bc7fb0e4354d3f2f5f3c 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserXmlAnonTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserXmlAnonTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserXmlAnonTest extends UserResourceTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserXmlBasicAuthTest.php b/core/modules/user/tests/src/Functional/Rest/UserXmlBasicAuthTest.php
index 25ee4e3e39122332aa7dc8d6f11f53a8a5be5f69..486c7a5d86e3292a30ba7cf3fa77e0aa1dca7e33 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserXmlBasicAuthTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserXmlBasicAuthTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserXmlBasicAuthTest extends UserResourceTestBase {
 
diff --git a/core/modules/user/tests/src/Functional/Rest/UserXmlCookieTest.php b/core/modules/user/tests/src/Functional/Rest/UserXmlCookieTest.php
index 6015e2df5530677d021e755cb4ada6225311203c..517e8fb9b128eb87eadac0880bfe93a179cbc4e4 100644
--- a/core/modules/user/tests/src/Functional/Rest/UserXmlCookieTest.php
+++ b/core/modules/user/tests/src/Functional/Rest/UserXmlCookieTest.php
@@ -7,6 +7,7 @@
 
 /**
  * @group rest
+ * @group #slow
  */
 class UserXmlCookieTest extends UserResourceTestBase {
 
diff --git a/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php b/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php
index 97d2ffc2c91b824d100f22600878a1e07e0ea0a5..6a4847219e0b1389a99cfde533307ad6a1b7bb6e 100644
--- a/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php
+++ b/core/modules/views/tests/src/Functional/Plugin/DisplayTest.php
@@ -12,6 +12,7 @@
  * Tests the basic display plugin.
  *
  * @group views
+ * @group #slow
  */
 class DisplayTest extends ViewTestBase {
 
diff --git a/core/modules/views/tests/src/Functional/Plugin/PagerTest.php b/core/modules/views/tests/src/Functional/Plugin/PagerTest.php
index 752fcafba4fb330316fbefc8fa28eab077790d84..64072bbf35ff5ca1ac43e96146918a76e4992c8c 100644
--- a/core/modules/views/tests/src/Functional/Plugin/PagerTest.php
+++ b/core/modules/views/tests/src/Functional/Plugin/PagerTest.php
@@ -12,6 +12,7 @@
  * Tests the pluggable pager system.
  *
  * @group views
+ * @group #slow
  */
 class PagerTest extends ViewTestBase {
 
diff --git a/core/modules/views_ui/tests/src/Functional/DisplayPathTest.php b/core/modules/views_ui/tests/src/Functional/DisplayPathTest.php
index d1228c8ae42408775613b8d5296dfa3c9cc5ea58..07d0178ff73fe29558a519105fd4ec63850b336a 100644
--- a/core/modules/views_ui/tests/src/Functional/DisplayPathTest.php
+++ b/core/modules/views_ui/tests/src/Functional/DisplayPathTest.php
@@ -11,6 +11,7 @@
  * Tests the UI of generic display path plugin.
  *
  * @group views_ui
+ * @group #slow
  * @see \Drupal\views\Plugin\views\display\PathPluginBase
  */
 class DisplayPathTest extends UITestBase {
diff --git a/core/modules/views_ui/tests/src/Functional/ExposedFormUITest.php b/core/modules/views_ui/tests/src/Functional/ExposedFormUITest.php
index c717f6ed5c5ed0502a157ba9aad85bb9daa89e10..033a2c8cf15259a7e0596f0ea9cfd59d3670f985 100644
--- a/core/modules/views_ui/tests/src/Functional/ExposedFormUITest.php
+++ b/core/modules/views_ui/tests/src/Functional/ExposedFormUITest.php
@@ -8,6 +8,7 @@
  * Tests exposed forms UI functionality.
  *
  * @group views_ui
+ * @group #slow
  */
 class ExposedFormUITest extends UITestBase {
 
diff --git a/core/modules/views_ui/tests/src/Functional/HandlerTest.php b/core/modules/views_ui/tests/src/Functional/HandlerTest.php
index e8bffb9ab3869de21fb0de0977cc8515b00839ce..bbda7d3fdb6dd426d84997cc19b04d2e57de496c 100644
--- a/core/modules/views_ui/tests/src/Functional/HandlerTest.php
+++ b/core/modules/views_ui/tests/src/Functional/HandlerTest.php
@@ -11,6 +11,7 @@
  * Tests handler UI for views.
  *
  * @group views_ui
+ * @group #slow
  * @see \Drupal\views\Plugin\views\HandlerBase
  */
 class HandlerTest extends UITestBase {
diff --git a/core/modules/views_ui/tests/src/Functional/PreviewTest.php b/core/modules/views_ui/tests/src/Functional/PreviewTest.php
index c8c6728df3562968f8c90f4608bec0c704657512..a6f1ca65d9b50be9aa620b4deaa4e40c532a589f 100644
--- a/core/modules/views_ui/tests/src/Functional/PreviewTest.php
+++ b/core/modules/views_ui/tests/src/Functional/PreviewTest.php
@@ -6,6 +6,7 @@
  * Tests the UI preview functionality.
  *
  * @group views_ui
+ * @group #slow
  */
 class PreviewTest extends UITestBase {
 
diff --git a/core/modules/views_ui/tests/src/Functional/ViewEditTest.php b/core/modules/views_ui/tests/src/Functional/ViewEditTest.php
index 6d957f6f14e7727bb3434b2288ad27a955fa6504..6ae48b98eaf48913ba4e0f3e2e1393529dd384e9 100644
--- a/core/modules/views_ui/tests/src/Functional/ViewEditTest.php
+++ b/core/modules/views_ui/tests/src/Functional/ViewEditTest.php
@@ -9,6 +9,7 @@
  * Tests some general functionality of editing views, like deleting a view.
  *
  * @group views_ui
+ * @group #slow
  */
 class ViewEditTest extends UITestBase {
 
diff --git a/core/modules/workflows/tests/src/Functional/WorkflowUiTest.php b/core/modules/workflows/tests/src/Functional/WorkflowUiTest.php
index d244bfe20db3b6c06fc06a9daaec989f3c98d3be..75ab3856340bf1960823279e1d8892d037b54363 100644
--- a/core/modules/workflows/tests/src/Functional/WorkflowUiTest.php
+++ b/core/modules/workflows/tests/src/Functional/WorkflowUiTest.php
@@ -10,6 +10,7 @@
  * Tests workflow creation UI.
  *
  * @group workflows
+ * @group #slow
  */
 class WorkflowUiTest extends BrowserTestBase {
 
diff --git a/core/modules/workspaces/tests/src/Functional/WorkspacePermissionsTest.php b/core/modules/workspaces/tests/src/Functional/WorkspacePermissionsTest.php
index 7d0a3175a5df3faaeb419efc27c226cdfa4a0e56..f0b3e2954646a3beccb425584ee90dde0bd77979 100644
--- a/core/modules/workspaces/tests/src/Functional/WorkspacePermissionsTest.php
+++ b/core/modules/workspaces/tests/src/Functional/WorkspacePermissionsTest.php
@@ -9,6 +9,7 @@
  * Tests permission controls on workspaces.
  *
  * @group workspaces
+ * @group #slow
  */
 class WorkspacePermissionsTest extends BrowserTestBase {
 
diff --git a/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php b/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
index 51dcda30490f407fe4dcec0e801a17059d767c6c..0116f511bbf4e2c10ee5a7b734a06e66ffe72c97 100644
--- a/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
+++ b/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
@@ -9,6 +9,7 @@
  * Tests the Olivero theme.
  *
  * @group olivero
+ * @group #slow
  */
 class OliveroTest extends BrowserTestBase {
 
diff --git a/core/themes/olivero/tests/src/Functional/Update/OliveroPostUpdateTest.php b/core/themes/olivero/tests/src/Functional/Update/OliveroPostUpdateTest.php
index 38c1d29930d055c61e0780128946a088820f8ab2..6625d58dd36e978b7047cac460954168fde132b1 100644
--- a/core/themes/olivero/tests/src/Functional/Update/OliveroPostUpdateTest.php
+++ b/core/themes/olivero/tests/src/Functional/Update/OliveroPostUpdateTest.php
@@ -8,6 +8,7 @@
  * Tests the update path for Olivero.
  *
  * @group Update
+ * @group #slow
  */
 class OliveroPostUpdateTest extends UpdatePathTestBase {