Currently, the API returns

"senderUserId" and "senderUsername" fields when Kick/Ban notification is received. I believe this to be a security/privacy concern in the future with larger groups as the person who was banned/kicked out could go after the person who banned them. Also, Usernames are no longer supposed to be used, yet they are still present here. Instead, the notification should likely have "senderGroupId" with no specific user.