I am getting a lot of spam detection false positives from SurgeMail. Many of them seem to refer to presence or lack of an AContent1 feature; almost all of them refer to a x-myrbl Unknown header, some refer to a x-myrbl Orange header. Does anyone have any idea or link to a page discussing what the x-spamdetect " AContent1 " header means exactly ? How about AContent3, BContent2 ?