[Dovecot] map_uid/GUID at IMAP level (IMAP extension?)

[Andrzej A. Filip]

Is map_uid/guid going to be supported at IMAP protocol level? [via IMAP
protocol extension]

Specifically I would like to be able to:
a) ask for mail_uid/GUID of specific message in mail store
b) get list of folders containing copies of message with given mail_uid/GUID

http://wiki2.dovecot.org/MailboxFormat/dbox#Multi-dbox

Related:
https://developers.google.com/google-apps/gmail/imap_extensions#access_to_the_gmail_unique_message_id_x-gm-msgid
[message to guid mapping]

https://developers.google.com/google-apps/gmail/imap_extensions#access_to_gmail_labels_x-gm-labels
[message to list of folders mapping]