how to check permission/access of objects/files in a s3 bucket?

I copy files to my s3 bucket , either with copy or sync commands with bucket owner flag. --acl bucket-owner-full-control

if this flag is not used, what is the default setting ?

also, how can i check the access control of any bucket/object ? is there a cli command or directly from the console. ?

aws s3 cp source destination --acl bucket-owner-full-control