Neos\FluidAdaptor\View\TemplatePaths::getPackagePrivateResourcesPath PHP Method

    protected function getPackagePrivateResourcesPath($packageKey)
    {
        if (!$this->packageManager->isPackageActive($packageKey)) {
            return null;
        }
        $packageResourcesPath = $this->packageManager->getPackage($packageKey)->getResourcesPath();
        return Files::concatenatePaths([$packageResourcesPath, 'Private']);
    }