Content Type for MHT files

Question

What is the content type for MHT files?

Answer 1

message/rfc822

RFC 822 - STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES

Here is a hyperlink: message/rfc822

Answer 2

application/octet-stream

You can stream the contents of a .eml file to a browser with this content type and .mht as the extension, and the email will be rendered similar to the way it is rendered in an email client.

Answer 3

Thank you, Guy, for bringing that up. Nearly every single discussion of MHT files that I see ends up including some statement about MHT being a "proprietary" format from Microsoft. Even worse, many of those statements are from people who are open standards advocates who bring it up as a degradation of the format.

Answer 4

Microsoft, who co-authored the spec for MHT, seem to think that it should be 'message/rfc822' on this support page.

No specific MIME type seems to be given in the spec though: RFC2557: MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)