User:Imz/mini-research on HOW TO edit received messages

(In search for a mail client (= MUA) that could edit the subject and insert comments: which MUAs can and which MUAs cannot do this?)

Although IMO this is not a sane will (to edit received messages; I'd recommend to annotate instead or use a completely different tool for one's task, like a VCS or wiki or DB), some people want this because they use this to implement the data-processing part of their job.

Probably, there is an unwieldy number of (even free) mail clients, so the main difficulty of this research is study all of them; otherwise this research is quite trivial, hence it's mini-research.

I'm interested mostly in free, cross-platform (GNU/Linux and Windows, although Windows is not obligatory) IMAP clients.