This means the email address is malformed, so we are not able to display it.
Rather than show a blank space, we display nobody@.
If they are in your Junk folder, then the server spam filter has already moved them there. There is nothing more you need to do. Rules won’t apply automatically to the Junk folder anyway.
Your server will empty the folder automatically after some time, usually about 30 days, but if you want it emptied more often without manually emptying it, there is a setting in Menu > Settings > General.
