WordPress at a glance
filter is not described

login_errors filter-hook . WP 2.1.0

Filters the error messages displayed above the login form.

Usage

add_filter( 'login_errors', 'filter_function_name_2082' );
function filter_function_name_2082( $errors ){
	// filter...

	return $errors;
}
$errors(string)
Login error message.

Where the hook is called

login_header()
WC_Form_Handler::process_login()
wp-login.php 227
echo '<div id="login_error">' . apply_filters( 'login_errors', $errors ) . "</div>\n";
woocommerce/includes/class-wc-form-handler.php 980
wc_add_notice( apply_filters( 'login_errors', $e->getMessage() ), 'error' );

Where the hook is used (in WP core)

Does not used.