[Dovecot] Sieve Editheader Extension?

I've done extensive searches, and there is virtually no information
about actual implementations of the draft Sieve Editheader Extension (which provides 'addheader' and 'deleteheader' actions):

http://www.ietf.org/internet-drafts/draft-ietf-sieve-editheader-11.txt

Is anyone currently working on this for Dovecot Sieve?

If not, are there any plans to do so? And before I start digging
through the source, is the architecture amenable to this functionality?

Thanks,

:: Mike ::