from docs/pop-imap.txt, it seems there is a AUTH=X-ZIMBRA support for imap access:
for Internet Message Access Protocol (IMAP)

Also support AUTH=X-ZIMBRA:
Initial (and only) SASL response is identical to that of AUTH PLAIN, except that X-ZIMBRA takes a valid Zimbra auth token
as the password (e.g. "authzid^@authcid^@authtoken"). The authtoken must match authcid, and then the normal authorization
check is made for authzid with the caveat that admin access is granted only if the supplied authtoken is an admin token.
though, after login with python's imaplib, there is no AUTH=X-ZIMBRA in CAPABILITY

< OLIN1 OK [CAPABILITY IMAP4rev1 ACL BINARY CATENATE CHILDREN CONDSTORE ENABLE ESEARCH ESORT I18NLEVEL=1 ID IDLE LIST-EXTENDED LIST-STATUS LITERAL+ LOGIN-REFERRALS MULTIAPPEND NAMESPACE QRESYNC QUOTA RIGHTS=ektx SASL-IR SEARCHRES SORT THREAD=ORDEREDSUBJECT UIDPLUS UNSELECT WITHIN XLIST] LOGIN completed
So I want to know how to enable AUTH=X-ZIMBRA and is there further information to expand on how to use AUTH=X-ZIMBRA?
thanks.