I use Opera, but I do not the M2 Opera mail client; I do not even have it active nor its menus.

You will need to copy the individual messages from a Pegasus folder to the Unix mailbox folder.

I suggest trying just a few messages at first to ensure that Opera does import the messages correctly. Once correct operation is confirmed, do one Pegasus folder at a time; Select All messages and use the Copy* button.
You may use more that one Unix mailbox folder, although multiple .MBX and .PMG file pairs may be confusing to import to Opera.

*Use Copy to ensure that no data is lost until the import confirmed successful.

Can someone explain to me in very simple terms how I can get my email into a format that can be used by Opera?

Thanks.

Try to copy messages to a "Unix Mailbox Format" folder in Pegasus
then use the Opera mbox import facility.
See: Import your messages

Create a new directory in Windows Explorer, e.g., C:\mailtmp
Then in Pegasus; Folders > Add mailbox to list...

In the "Add a mailbox to your folder list" dialog:

Properties for mailbox
[x] Directory path
C:\mailtemp

Name for mailbox in folder listing
mailtemp [optional]

Now in Pegasus Mail folder listing you see the mounted mailbox.
- Do not use the "New mail folder"

Create a new folder in the mounted mailbox

In the" Enter name for folder or tray" dialog:

Name and type for new folder
SomeName
[x] Message folder "Unix Mailbox Format"
[] Enable autofiltering in the new folder

Thanks, Guy, but I'm not clear how this will help me. Will I then have files in a format that I can import into Opera?

Sorry, just noticed in your first sentence, "then use the Opera mbox import facility." I should try it out before I complain that it doesn't work!

Okay, I've got as far as the end of your instructions. Now what? I've made a new mailbox and a new folder inside the mailbox. Do I move all my existing mail folders into the new one? Or just copy them? Does it  make a difference?

Well, I've discovered I can't simply copy a mailbox into the new mailbox. I have a horrible feeling I know the next step -- copying folder by laborious folder. Or worse-- email by email.

Am I right? Anybody?