You can use this operation to modify an object ACL.
OBS allows you to control access permission for objects. By default, only an object creator can access the object. However, the creator can set an access policy (such as a public access policy) to grant READ permission for the object to other users. For the object in SSE-KMS model, it does not take effect.
You can set an access control policy when uploading an object or send PUT Object acl or GET Object acl request to modify or obtain the object ACL.
By default, this operation modifies the ACL of an object of the latest version. You can specify versionId to modify the ACL of an object of the desired version.