Definition for "skipped" in "_shards" as query result

[junkoshimane]

Hi all,

Regarding "skipped" in "_shards" as query result, it is defined nowhere even in the following URL.
https://www.elastic.co/guide/en/elasticsearch/reference/current/_the_search_api.html

{
  "took" : 5,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0, <============== Definition ?????
    "failed" : 0
  },

I found the similar topic in this discuss site but nobody comments.
https://discuss.elastic.co/t/understanding-skipped-shards/141428

Definitely, we don't know in which case "skipped" is counted.

Only if the follwing case is applicable, is it counted?
Are shards skipped when a range query does not create hits
https://discuss.elastic.co/t/are-shards-skipped-when-a-range-query-does-not-create-hits/120239/

[MaJaHa95 (Matthew Haugen)]

I am, indeed, still curious about this as well!

[junkoshimane]

none ???