Theme_My_Login_Form_Field::get_description()

public function get_description() {
    /**
     * Filters the form field description.
     *
     * @param string                    $description The field Description.
     * @param Theme_My_Login_Form_Field $field       The field object.
     */
    return apply_filters( 'tml_get_form_field_description', $this->description, $this );
}

View src/includes/class-theme-my-login-form-field.php, line 296 on GitHub