These are additional headers which are sent amongst the regular message as the part of the PHP's function mail()
. In the manual they are displayed as $additional_headers
. miniBB uses such headers in sendMail() function of bb_functions.php file. If your email message is displaying headers as the regular text, it could be because your server is running in Safe Mode or because of the improper configuration of the external mailing program, or... for another reason which I only could suppose.
You may try to edit
mail($email, $subject, $msg, $from_email);
string in the function I've mentioned removing $from_email
so it appears like
mail($email, $subject, $msg);