1) Attach a file to a message.
2) Right-click the attachment, choose Properties and change the attachment's name.

Result: The "Content-Type" "name" attribute is changed, as follows:

Content-Type: application/pdf; name="new_name.pdf"

The "Content-Disposition" "filename" attribute stays unchanged, though:

Content-Disposition: attachment; filename="orig_name.pdf"


Somewhat counter-intuitive, this will in most cases cause the attachment to be called "orig_name.pdf" on the receiver's side, not "new_name.pdf" as one might expect when using the properties dialog.

By default, the name and filename attributes are set to the same values by kMail, as far as I can see.

Either the "name" field should change both values, or there should be a separate "File Name" property.

Maybe interesting in this regard:

https://mailarchive.ietf.org/arch/msg/ietf-smtp/KtN0TdoHDayKvKycNbsFD-GB-e4#

Wishlist item Bug #311179 may be related.