rties defined by the
        <a href="https://www.w3.org/TR/activitystreams-vocabulary/">Vocabulary</a>:
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-actor">actor</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-object-term">object</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-target">target</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-orig