17 methods override FormElementBase::valueCallback()

Checkbox::valueCallback in core/lib/Drupal/Core/Render/Element/Checkbox.php
Checkboxes::valueCallback in core/lib/Drupal/Core/Render/Element/Checkboxes.php
Datelist::valueCallback in core/lib/Drupal/Core/Datetime/Element/Datelist.php
Validates the date type to adjust 12 hour time and prevent invalid dates. If the date is valid, the date is set in the form.
Datetime::valueCallback in core/lib/Drupal/Core/Datetime/Element/Datetime.php
File::valueCallback in core/lib/Drupal/Core/Render/Element/File.php
FormElement::valueCallback in core/lib/Drupal/Core/Render/Element/FormElement.php
ImageButton::valueCallback in core/lib/Drupal/Core/Render/Element/ImageButton.php
ManagedFile::valueCallback in core/modules/file/src/Element/ManagedFile.php
Password::valueCallback in core/lib/Drupal/Core/Render/Element/Password.php
PasswordConfirm::valueCallback in core/lib/Drupal/Core/Render/Element/PasswordConfirm.php
Radios::valueCallback in core/lib/Drupal/Core/Render/Element/Radios.php
Range::valueCallback in core/lib/Drupal/Core/Render/Element/Range.php
Select::valueCallback in core/lib/Drupal/Core/Render/Element/Select.php
Table::valueCallback in core/lib/Drupal/Core/Render/Element/Table.php
Textarea::valueCallback in core/lib/Drupal/Core/Render/Element/Textarea.php
Textfield::valueCallback in core/lib/Drupal/Core/Render/Element/Textfield.php
Token::valueCallback in core/lib/Drupal/Core/Render/Element/Token.php

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