code: public function getFileContent($file, $identifier)
      {
          if ($this->fallbackDriver) {
              return $this->fallbackDriver->getFileContent($file, $identifier);
          }
  
          if (strpos($identifier, '/') !== false) {
              $branches = $this->getBranches();
              if (isset($branches[$identifier])) {
                  $identifier = $branches[$identifier];
              }
          }
  
          $resource = sprintf(
              'https://api.bitbucket.org/2.0/repositories/%s/%s/src/%s/%s',
              $this->owner,
              $this->repository,
              $identifier,
              $file
          );
  
          return $this->getContentsWithOAuthCredentials($resource);
      }
docs: {@inheritdoc}