tml_ms_register_default_actions()

function tml_ms_register_default_actions() {
    tml_register_action(
        'signup',
        array(
            'title'             => '',
            'slug'              => 'signup',
            'callback'          => 'tml_ms_signup_handler',
            'network'           => true,
            'show_on_forms'     => false,
            'show_in_widget'    => false,
            'show_in_nav_menus' => false,
        )
    );

    tml_register_action(
        'activate',
        array(
            'title'             => '',
            'slug'              => 'activate',
            'callback'          => 'tml_ms_activation_handler',
            'network'           => true,
            'show_on_forms'     => false,
            'show_in_widget'    => false,
            'show_in_nav_menus' => false,
        )
    );
}

View src/includes/ms-functions.php, line 15 on GitHub