code: public function getFileContent($file, $identifier)
      {
          if ($this->gitDriver) {
              return $this->gitDriver->getFileContent($file, $identifier);
          }
  
          $resource = $this->getApiUrl() . '/repos/'.$this->owner.'/'.$this->repository.'/contents/' . $file . '?ref='.urlencode($identifier);
          $resource = JsonFile::parseJson($this->getContents($resource));
          if (empty($resource['content']) || $resource['encoding'] !== 'base64' || !($content = base64_decode($resource['content']))) {
              throw new \RuntimeException('Could not retrieve ' . $file . ' for '.$identifier);
          }
  
          return $content;
      }
docs: {@inheritdoc}