8 methods override FieldItemBase::mainPropertyName()

CommentItem::mainPropertyName in core/modules/comment/src/Plugin/Field/FieldType/CommentItem.php
EntityReferenceItem::mainPropertyName in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
LayoutSectionItem::mainPropertyName in core/modules/layout_builder/src/Plugin/Field/FieldType/LayoutSectionItem.php
LinkItem::mainPropertyName in core/modules/link/src/Plugin/Field/FieldType/LinkItem.php
MapItem::mainPropertyName in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/MapItem.php
MultiValueTestItem::mainPropertyName in core/modules/system/tests/modules/entity_test_update/src/Plugin/Field/FieldType/MultiValueTestItem.php
PathItem::mainPropertyName in core/modules/path/src/Plugin/Field/FieldType/PathItem.php
ShapeItem::mainPropertyName in core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldType/ShapeItem.php

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