code: public function copyTo($file, $target)
      {
          if ($this->enabled) {
              $file = preg_replace('{[^'.$this->whitelist.']}i', '-', $file);
              if (file_exists($this->root . $file)) {
                  try {
                      touch($this->root . $file, filemtime($this->root . $file), time());
                  } catch (\ErrorException $e) {
                      // fallback in case the above failed due to incorrect ownership
                      // see https://github.com/composer/composer/issues/4070
                      Silencer::call('touch', $this->root . $file);
                  }
  
                  $this->io->writeError('Reading '.$this->root . $file.' from cache', true, IOInterface::DEBUG);
  
                  return copy($this->root . $file, $target);
              }
          }
  
          return false;
      }
docs: Copy a file out of the cache