anchor.diff:  --------------------------------------------------
   // TESTRESPONSE[s/"_seq_no" : \d+/"_seq_no" : $body._seq_no/ s/"_primary_term" : 1/"_primary_term" : $body._primary_term/]
   
  -
   Field values fetched from the document itself are always returned as an array.
  -Since the `counter` field is not stored the get request simply ignores it when trying to get the `stored_fields.`
  -
  -It is also possible to retrieve metadata fields like the `_routing` field:
  +Since the `counter` field is not stored, the get request  ignores it.
  +
  +You can also retrieve metadata fields like the `_routing` field:
   
   [source,js]
   --------------------------------------------------
  
positive.code: --------------------------------------------------
  // TESTRESPONSE[s/"_seq_no" : \d+/"_seq_no" : $body._seq_no/ s/"_primary_term" : 1/"_primary_term" : $body._primary_term/]
  
  The above result includes the `_index`, `_id`, and `_version`
  of the document we wish to retrieve, including the actual `_source`
  of the document if it could be found (as indicated by the `found`
  field in the response).
  
  The API also allows to check for the existence of a document using
  `HEAD`, for example:
  
  [source,js]
  --------------------------------------------------
  
negative.code: --------------------------------------------------
  // TESTRESPONSE[s/"_seq_no" : \d+/"_seq_no" : $body._seq_no/ s/"_primary_term" : 1/"_primary_term" : $body._primary_term/]
  
  Only leaf fields can be retrieved with the `stored_field` option. Object fields
  can't be returned--if specified, the request fails.
  