This article isnt about how emails associated with logins got released in a breach, but that documents that are uploaded to the archive are stamped with the email address of the account that uploaded it and that can be viewed by anyone who downloads the document.
So in standard, everyday use of the site, email addresses are being revealed and are associated with the actions of that person. Like if I upload a copy of the manual for my washing machine or something, which is a more benign example, my email is linked to that document now.
Then combine this with (1) the internet archive says in multiple spots that they dont reveal this info anywhere, and (2) the issue has been raised to the organization, and it becomes more of a specific negligence from them.
This looks like a good backend for sure, but the web frontends look a little lacking and I'm not seeing anything about a mobile frontend (other than if a web one was up, which would be fine). Have you tried any of the web frontends?