de><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-to">to</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-bto">bto</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-cc">cc</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-bcc">bcc</a></code> |
          <code><a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-mediatype">mediaType</a></code> |
          <c