Trying to look inside an Outlook template but your current mail program won’t open it? This thread walks you through an easier solution that avoids complicated manual steps. The MSOutlookHelp OFT Converter lets you open OFT File on Mac by converting the template into formats that are widely supported, such as MSG and EML. It also lets you preview the content before conversion, giving you a good idea of what will be exported. Another nice feature is that it keeps all attachments together with the email content so nothing is left behind.

For more: https://www.msoutlookhelp.com/blog/open-oft-file/