I'm trying to read some old emails in an account from around 20 years ago that I have kept in Thunderbird the entire time. I stopped using the account, but kept it configured as it always had been with the old email saved in it. The emails are in several folders in Thunderbird, and I can see them listed when I select a folder, but the content of most of them is now invisible. For many years I upgraded Thunderbird and they remained visible, and I naively assumed that would always be the case. I think the visibility problem happened after a Thunderbird upgrade sometime within the last few years. Strangely, a few emails are readable. I think they're the last ones I viewed before I became unable to see additional ones I select to view. I believe all the data is still there, but I don't know how to read it. In the file system, here's what my Thunderbird profile Mail directory looks like: /Users/myMacUser/Library/Thunderbird/Profiles/my-random.default/Mail account.server.name - TB Email Folder 1.sbd (empty directory) - TB Email Folder 1 (no file extension, apparently the file containing the email data. File sizes suggest they contain data) - TB Email Folder 1.msf (the index file, apparently readable) etc. I'm using Thunderbird 115.12.2 on MacOS Sonoma 14.5. I tried several types of exports with the ImportExportTools NG extension, but it just exported zero byte or blank files for the invisible emails. How do I read these folder data files?