Contribution API does not retrieve honor_contact_id

Even though honor_contact_id shows up in the api/doc list, when retrieving a contribution record, the honor_contact_id field isn't retrieved. Attempted to use getvalue with same result. For example:
http://drupal.demo.civicrm.org/civicrm/api/explorer#/civicrm/ajax/rest?entity=Contribution&action=getvalue&id=45&return=honor_contact_id&debug=1&sequential=1&json=1

gives the error

{ "invalid_field":"honor_contact_id", "is_error":1, "error_message":"field honor_contact_id unset or not existing" }