account_indexes

raw details (from release v2.2.3):

{
  "name": "account_indexes",
  "properties": {
    "long": "account-index",
    "takes_value": "true",
    "multiple": "true",
    "possible_values": "&[\"program-id\", \"spl-token-owner\", \"spl-token-mint\"]",
    "value_name": "INDEX",
    "help": "Enable an accounts index, indexed by the selected account field"
  },
  "isDeprecated": false
}