What does "restricted indices" means in Security:Has privileges API?

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Hi @LoadingZhang,

Restricted indices (currently only .security* ) are special internal indices that require setting the allow_restricted_indices flag on every index permission that covers them. If this flag is false (default) the permission will not cover these and actions against them will not be authorized.

The security index is used by the security module to provide security features for ES.
When you define index privilege you can use allow_restricted_indices flag to authorize the user access to restricted indices.
Hope this helps.

Thanks and Regards,
Yogesh Gaikwad