anchor.diff:  [[search-rank-eval-api-path-params]]
   ==== {api-path-parms-title}
   
  -`<index>`::
  - (Required, string) Comma-separated list or wildcard expression of index names
  - used to limit the request.
  +`<target>`::
  +(Optional, string)
  +Comma-separated list of data streams, indices, and index aliases used to limit
  +the request. Wildcard (`*`) expressions are supported.
  ++
  +To target all data streams and indices in a cluster, omit this parameter or use
  +`_all` or `*`.
   
   [[search-rank-eval-api-query-params]]
   ==== {api-query-parms-title}
  
positive.code: [[search-rank-eval]]
  === Ranking Evaluation API
  
  Allows you to evaluate the quality of ranked search results over a set of 
  typical search queries.
  
negative.code: things:
  
  . A collection of documents you want to evaluate your query performance against, 
    usually one or more data streams or indices.
  . A collection of typical search requests that users enter into your system.
  . A set of document ratings that represent the documents' relevance with respect
    to a search request.
  