If you are searching for useful tool to transfer Zimbra file to Outlook, then you can use Zimbra to Outlook Converter.
Some features are:
• This application also transfers Zimbra contacts and calendar to Outlook PST file format.
• This application convert TGZ file to numerous file formats for example PST, EML, EMLX, HTML, OLM, NSF, MBOX, and etc.
Read more:
https://www.kdetools.com/zimbra/