[Users] How to export and import message trees?

[Ben Stover]

Sorry for this question.
I am currently evaluating Claws Mail.

One of the most important features of an email client for me is that I can export (and import) certain message trees.

Assume I have created a new folder "archive" which in turn contains three sub-folders
"2012", "2013", "2014"

Now I want to export all messages (but only those) from folder

archive\2013\

How can I do this?

Can I export it e.g. on ClawsMail installation 1 (=e.g. my Deskop computer) then transfer the
packed backup to my Notebook and my ClawsMail installation over there and then import the
msg tree over there?

Which storage format is used in general in ClawsMail? Mbox?

Can I switch to *.MSG?

Can I at least export and import *.MSF messages?

Thank you
Ben