OE and MIME types

I asked the following in microsoft.public.outlookexpress.general recently
but no-one has answered. Does anyone here know?



I don't use OE so have little idea how it does things. Someone recently
used OE to send me a mail with a file attached to it. The file contained
plain text but the extension - ".MUP" isn't a well-known one.

OE prefaced the attached content with:

Content-Type: application/octet-stream;
name="xyz.MUP"
Content-Transfer-Encoding: quoted-printable

When detached, this file had lost its embedded carriage-returns.


If, using a text editor on the raw message data, I change the attachment's
content-type to

Content-Type: text/plain;
name="xyz.MUP"
Content-Transfer-Encoding: quoted-printable

then the file when I detach it ends up properly formed.


Is this a symptom of an OE problem? Is there something the sender should
have done, either to have the file attached and described as plain text
despite its file extension, or to have it - say - base64-encoded (which is
what my own email client does when asked to send a non-obvious file type)?


How in general does OE know what to do when sending a strange file type?
When the application that owns the .MUP filetype is installed should it
somehow define (via the registry?) the way that MIME should handle such a
file?

--
Jeremy C B Nicoll - my opinions are my own.

Email sent to my from-address will be deleted. Instead, please reply
to replacing "nnn" by "284".