15 files declare their use of LayoutDefault

BlankLayout.php in core/modules/layout_builder/src/Plugin/Layout/BlankLayout.php
FieldLayoutBuilderTest.php in core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php
Layout.php in core/lib/Drupal/Core/Layout/Attribute/Layout.php
Layout.php in core/lib/Drupal/Core/Layout/Annotation/Layout.php
LayoutBuilderTestPlugin.php in core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Layout/LayoutBuilderTestPlugin.php
LayoutDefaultTest.php in core/tests/Drupal/Tests/Core/Layout/LayoutDefaultTest.php
LayoutPluginManagerTest.php in core/tests/Drupal/Tests/Core/Layout/LayoutPluginManagerTest.php
LayoutTestDependenciesPlugin.php in core/modules/system/tests/modules/layout_test/src/Plugin/Layout/LayoutTestDependenciesPlugin.php
LayoutTestPlugin.php in core/modules/system/tests/modules/layout_test/src/Plugin/Layout/LayoutTestPlugin.php
LayoutWithoutLabel.php in core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Layout/LayoutWithoutLabel.php
MultiWidthLayoutBase.php in core/modules/layout_builder/src/Plugin/Layout/MultiWidthLayoutBase.php
NavigationLayout.php in core/modules/navigation/src/NavigationLayout.php
TestContextAwareLayout.php in core/modules/layout_builder/tests/modules/layout_builder_test/src/Plugin/Layout/TestContextAwareLayout.php
TestLayoutContentFooter.php in core/modules/field_layout/tests/modules/field_layout_test/src/Plugin/Layout/TestLayoutContentFooter.php
TestLayoutMainFooter.php in core/modules/field_layout/tests/modules/field_layout_test/src/Plugin/Layout/TestLayoutMainFooter.php

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