[bug-mailutils] multipart/alternative not displaying in Yahoo.com

[Jean Louis]

Hello,

When I send mailing, the multipart/alternative is not displaying in
Yahoo.com

When I receive email from leadpages.com into Yahoo, I can see they
have it as multipart/related that includes the multipart/alternative

Please review, how we can do it that it is really deliverable by using
mail from mailutils?

Imagine, sending multipart/alternative with text and html together is
displaying in Yahoo as having attachments. So something is certainly
wrong.

Do you know what?

Jean