To view a read-only copy of your Google Mail mailbox, you can use Apple Mail on your Mac.
- Launch the Mail app on your Mac.
- If you haven't set up Apple Mail already, you'll need to set it up with at least one email account that isn't your Kenyon email account. Instructions vary depending on the exact email provider that you have.
- After Mail has been set up, in the menu bar, go to File > Import Mailboxes....
- In the dialog box that shows, point the mailbox option to the MBOX file that Google Takeout gave you.
- Import the mailbox. You should see your messages show up in Apple Mail in a separate folder. This is a read-only copy of your email. You won't be able to send any email from your Kenyon account, but you will be able to view any email that you've received.