Neos\Neos\Controller\Module\Administration\SitesController::createSitePackageAction PHP Method

    public function createSitePackageAction($packageKey, $siteName)
    {
        if ($this->packageManager->isPackageActive('Neos.SiteKickstarter') === false) {
            $this->addFlashMessage('The package "%s" is required to create new site packages.', 'Missing Package', Message::SEVERITY_ERROR, array('Neos.SiteKickstarter'), 1475736232);
            $this->redirect('index');
        }
        if ($this->packageManager->isPackageAvailable($packageKey)) {
            $this->addFlashMessage('The package key "%s" already exists.', 'Invalid package key', Message::SEVERITY_ERROR, array(htmlspecialchars($packageKey)), 1412372021);
            $this->redirect('index');
        }
        $generatorService = $this->objectManager->get(GeneratorService::class);
        $generatorService->generateSitePackage($packageKey, $siteName);
        $this->flashMessageContainer->addMessage(new Message(sprintf('Site Packages "%s" was created.', htmlspecialchars($packageKey))));
        $deactivatedSitePackages = $this->deactivateAllOtherSitePackages($packageKey);
        if (count($deactivatedSitePackages) > 0) {
            $this->flashMessageContainer->addMessage(new Message(sprintf('The existing Site Packages "%s" were deactivated, in order to prevent interactions with the newly created package "%s".', htmlspecialchars(implode(', ', $deactivatedSitePackages)), htmlspecialchars($packageKey))));
        }
        $this->packageManager->activatePackage($packageKey);
        $this->forward('importSite', null, null, ['packageKey' => $packageKey]);
    }