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
octet-stream
organization
pgp
-pgp-encrypt
+pgp-encrypted
pgp-keys
pgp-signed
pkcs7-mime
x-comment-to
x-convert
x-label
+x-mutt-deleted
x-pgp-message
x-pkcs7-mime
xref