ese include:
        <code>
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-attachment">attachment</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-attributedto">attributedTo</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-audience">audience</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-content">content</a></code> |
          <code><a href="https