apparently-from
apparently-to
application
-application/postscript
application/pgp-encrypted
application/pgp-signature
application/pkcs7-signature
+application/postscript
application/x-pkcs7-signature
audio
base64
external-body
followup-to
from
+html
image
in-reply-to
iso-2022-jp
message
message-id
mime-version
+mixed
model
multipart
multipart/mixed
octet-stream
organization
pgp
-pgp-encrypt
+pgp-encrypted
pgp-keys
+pgp-signature
pgp-signed
pkcs7-mime
+pkcs7-signature
plain
postscript
print
x-comment-to
x-convert
x-label
+x-mutt-deleted
x-pgp-message
x-pkcs7-mime
+x-pkcs7-signature
xref
x-status
x-uuencode