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Pretty simple. On the Replays page when you search replays for a particular format, it will show the battle's rating under the "Highest rated" category in the blue box itself (check the spoilers below) but doesnt do the same in the "Newest" category. It would be quite nice to have this feature...
The command /ionext exists but it just makes your very next battle invite only. It would be a lot more convenient for players who want to play in shadow if a command is made such that all battles can be made 'invite only' till it is turned off