I think a browser extension which people who have access to the article use to send the article data to the archive server.
In that case, the government is fine with it.
1: https://chrome.google.com/webstore/detail/archive-page/gcaim...
I think the distinction between the two is moot in this post. The question could very well have been "How does archive.org bypass paywalls?" Though it's interesting that archive.is seems to just crawl the URL. Indeed that means they wouldn't necessarily be able to bypass the paywall.
Also, extension likely has also terms of usage prohibiting uploading copyrighted content shifting liability on users.
They went after seeders