Theme_My_Login::register_action()

public function register_action( Theme_My_Login_Action $action ) {

    $this->actions[ $action->get_name() ] = $action;

    $action->add_callback_hook();
    $action->add_ajax_callback_hook();

    /**
     * Fires after registering an action.
     *
     * @since 7.0
     *
     * @param string                $name   The action name.
     * @param Theme_My_Login_Action $action The action object.
     */
    do_action( 'tml_registered_action', $action->get_name(), $action );

    return $action;
}

View src/includes/class-theme-my-login.php, line 74 on GitHub