OpenSearch/rest-api-spec/api/indices.open.json

{
  "indices.open": {
    "documentation": "",
    "methods": ["POST"],
    "url": {
      "path": "/{index}/_open",
      "paths": ["/{index}/_open"],
      "parts": {
        "index": {
        }
      },
      "params": {
        "index": {
        },
        "timeout": {
        }
      }
    },
    "body": null
  }
}