SpamAssassin Rule: MIME_QP_LONG_LINE
Standard description: Quoted-printable line longer than 76 chars
The Quoted-Printable encoding REQUIRES that encoded lines be no more than 76 characters long. See RFC 2045.
The default scores for this rule can be found in the online list of tests.
Although the Quoted-Printable specification requires lines be no more than 76 characters, many implementations ignore this and use a suggested line limit from RFC 5322 of 78 characters. Therefore it is not unusual to see this rule triggered by non-spam. See Bug 5491.