FluidTYPO3\Flux\View\TemplatePaths::resolveAvailableLayoutFiles PHP Method

    public function resolveAvailableLayoutFiles($format = self::DEFAULT_FORMAT)
    {
        return $this->resolveFilesInFolders($this->getLayoutRootPaths(), $format);
    }

 /**
  * Renders a Fluid Template Layout select field
  *
  * @param array $parameters
  * @param mixed $pObj
  * @return string
  */
 public function addLayoutOptions(&$parameters, &$pObj)
 {
     $referringField = $parameters['config']['arguments']['referring_field'];
     $currentValue = $parameters['row'][$referringField];
     $configuration = $this->configurationService->getViewConfigurationByFileReference($currentValue);
     $templatePaths = new TemplatePaths($configuration);
     $files = $templatePaths->resolveAvailableLayoutFiles();
     $files = array_map('basename', $files);
     foreach ($files as $file) {
         if (0 !== strpos($file, '.')) {
             $file = pathinfo($file, PATHINFO_FILENAME);
             array_push($parameters['items'], [$file, $file]);
         }
     }
 }