code: public static function getTemplate($strTemplate)
  	{
  		$strTemplate = basename($strTemplate);
  
  		// Check for a theme folder
  		if (\defined('TL_MODE') && TL_MODE == 'FE')
  		{
  			/** @var PageModel $objPage */
  			global $objPage;
  
  			if ($objPage->templateGroup != '')
  			{
  				if (Validator::isInsecurePath($objPage->templateGroup))
  				{
  					throw new \RuntimeException('Invalid path ' . $objPage->templateGroup);
  				}
  
  				return TemplateLoader::getPath($strTemplate, 'html5', $objPage->templateGroup);
  			}
  		}
  
  		return TemplateLoader::getPath($strTemplate, 'html5');
  	}
docs: Find a particular template file and return its path
  
  @param string $strTemplate The name of the template
  
  @return string The path to the template file
  
  @throws \RuntimeException If the template group folder is insecure