Bug: pdf attachments - Content-Type: application/x-unknown-content-type;
Status: NEW
Priority: --
Created: 2022-04-25 15:52:31+00:00
Resolved: 2022-04-25 16:05:38+00:00

Windows 10
Thunderbired version 

There seems to be a problem with 'Content-Type' when attaching document eg: pdf - via drag and drop sourced from a received email, although same pdf is ok if forwarded

TEST 1
Assume *.pdf file is a file stored on your computer in a folder,
Open Write and use 'attach' or drag and drop
If you hover over the attachment it will say exactly where that file is stored - the file directory.
eg: file:///C:Users/Username/Documents/Pets/cat.pdf
save as draft and source says:
Content-Type: multipart/mixed;
This is a multi-part message in MIME format.
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Type: application/pdf; name="cat.pdf"
Content-Disposition: attachment; filename="cat.pdf"
Content-Transfer-Encoding: base64

Note: Content-Type says: application/pdf
All OK

---------------------------------------

TEST 2
If you 'Forward' an email that has pdf attachments .
SAve as draft and view source.
Content-Type: multipart/mixed; 
This is a multi-part message in MIME format.
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Type: application/pdf; name="dogs.pdf"
Content-Disposition: attachment; filename="dogs.pdf"
Content-Transfer-Encoding: base64

Note: Content-Type: application/pdf; 
All OK

---------------------------------------

TEST 3
If you 'Forward' an email that has pdf attachment and then you add another attachment from a received email:
SAve as draft and view source.
Content-Type: multipart/mixed; 
This is a multi-part message in MIME format.
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Type: application/pdf; name="dogs.pdf"
Content-Disposition: attachment; filename="dogs.pdf"
Content-Transfer-Encoding: base64
Content-Type: application/x-unknown-content-type; name="cat.pdf"
Content-Disposition: attachment; filename="cat.pdf"
Content-Transfer-Encoding: base64

Note: 
original pdf is : Content-Type: application/pdf; 
but added pdf is : Content-Type: application/x-unknown-content-type;

Does not seem OK.

------------------------------

TEST 4 
If pdf is a pdf attachment in a received email or one stored in a test draft (previously attached from a file on computer) and you drag and drop the pdf attachment from received/draft email into new Write email, then the hover over attachment will say:
eg: mailbox:///C:Users/Username/Appdata/Roaming/Thunderbird/Profiles/profilename/Mail/mail account name/Drafts?number=1003&part=1.2&filename=cat.pdf

save as draft and view source says:
Content-Type: multipart/mixed;
This is a multi-part message in MIME format.
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Type: application/x-unknown-content-type; name="cat.pdf"
Content-Disposition: attachment; filename="cat.pdf"
Content-Transfer-Encoding: base64

Note: Content-Type: application/x-unknown-content-type;

If sent and received it still has Content-Type: application/x-unknown-content-type;

Is this intentional and can it be explained ?
Should attached pdf regardless of whether sourced from stored desktop file or an attachment always be Content-Type: application/pdf ?