anchor.diff:  // TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
   
   <1> The `key_as_string` value represents midnight on each day
  -    in the specified time zone.
  +    in the specified timezone.
   
   WARNING: When using time zones that follow DST (daylight savings time) changes,
   buckets close to the moment when those changes happen can have slightly different
  -sizes than would be expected from the used `interval`.
  +sizes than you would expect from the used `interval`.
   For example, consider a DST start in the `CET` time zone: on 27 March 2016 at 2am,
  -clocks were turned forward 1 hour to 3am local time. When using `day` as `interval`,
  +clocks were turned forward 1 hour to 3am local time. If you use `day` as `interval`,
   the bucket covering that day will only hold data for 23 hours instead of the usual
  -24 hours for other buckets. The same is true for shorter intervals like e.g. 12h.
  -Here, we will have only a 11h bucket on the morning of 27 March when the DST shift
  +24 hours for other buckets. The same is true for shorter intervals, like 12h,
  +where you'll have only a 11h bucket on the morning of 27 March when the DST shift
   happens.
   
  -
  -==== Offset
  -
  -The `offset` parameter is used to change the start value of each bucket by the
  +===== Offset
  +
  +Use the `offset` parameter to change the start value of each bucket by the
   specified positive (`+`) or negative offset (`-`) duration, such as `1h` for
   an hour, or `1d` for a day. See <<time-units>> for more possible time
   duration options.
   
  -For instance, when using an interval of `day`, each bucket runs from midnight
  -to midnight.  Setting the `offset` parameter to `+6h` would change each bucket
  +For example, when using an interval of `day`, each bucket runs from midnight
  +to midnight.  Setting the `offset` parameter to `+6h` changes each bucket
   to run from 6am to 6am:
   
   [source,js]
  
positive.code: ---------------------------------
  // CONSOLE
  
  UTC is used if no time zone is specified, which would result in both of these
  documents being placed into the same day bucket, which starts at midnight UTC
  on 1 October 2015:
  
  
negative.code: // CONSOLE
  // TEST[setup:sales]
  
  ===== Keys
  
  Internally, a date is represented as a 64 bit number representing a timestamp
  in milliseconds-since-the-epoch (01/01/1970 midnight UTC). These timestamps are
  returned as the ++key++ name of the bucket. The `key_as_string` is the same
  timestamp converted to a formatted
  date string using the `format` parameter sprcification:
  
  TIP: If you don't specify `format`, the first date
  <<mapping-date-format,format>> specified in the field mapping is used.
  
  [source,js]
  --------------------------------------------------
  