Gmail, Thunderbird, Netscape, Apple Mail, and various email client provides mailboxes in MBOX file format. But a user can also view the MBOX file without any email client installation.
Yes, if you want to open and read MBOX email then go with MailsDaddy Free MBOx Viewer tool. This freeware solution supports all Windows OS and allows users to open MBOX files with a few simple clicks. The software manages folders, subfolders, inline images, attachments, etc. in a display window.
Read more: https://www.mailsdaddy.com/free-mbox-viewer/