I have some emails where the Subject line has been wrapped, and subsequent lines are indented with TAB characters. Specifically, here's a dump of a portion of an email:

0002020 C c : sp nl S u b j e c t : sp [ B 0002040 u i l d b o t ] sp B u i l d B o 0002060 t sp S U C C E S S nl ht ( B l d _ 0002100 g s s d k _ g s s d k _ t e s t 0002120 _ 2 0 0 6 _ 0 9 _ 1 2 _ 0 0 _ 0 0002140 1 _ 0 0 _ I n c r e m e n t a l 0002160 _ 2 ) nl X - B e e n T h e r e :

Note the HT about half way through the third line.

When I view this email using Thunderbird 1.5.0.5 on Windows XP, with Dovecot 1.0.rc7 running on CentOS 4.3, this TAB character shows up as a funny character in the subject line, as displayed by the Thunderbird.

My question is: Should Dovecot be detecting mail header continuation lines that start with a TAB, and stripping the TAB (converting to a space)? I *think* that's what the RFCs implied when I read up on this a few months ago, but I may easily be mis-remembering.

A second somewhat off-topic question: When the automated system that sends out these messages sends them to me directly, this problem does not occur, because the email titles are not wrapped. However, when I receive these emails via a mailman mailing list, mailman prepends the text "[Buildbot]" on the front of the title, thus making the title long enough to require wrapping. As such, I imagine that it's mailman that is indenting the Subject continuation line with the TAB character. Is there an issue in mailman - should mailman be indenting with e.g. a SPACE character, or is mailman's action perfectly legal?

Thanks for any pointers.