The name of a callback function that returns default values. The function will be called with the following arguments:

public FieldConfigBase::getSetting($setting_name)

public FieldConfigBase::postCreate(EntityStorageInterface $storage)

The field type. This property is denormalized from the field storage for optimization of the "entity and render cache hits" critical paths.

public FieldConfigBase::getDefaultValue(FieldableEntityInterface $entity)

Flag indicating whether the field is translatable. Defaults to TRUE. Type: bool

public FieldConfigBase::setSetting($setting_name, $value)

public FieldConfigBase::postSave(EntityStorageInterface $storage, $update

Default field value. The default value is used when an entity is created, either: through an entity creation

public FieldConfigBase::getConfig($bundle)