: Legitimate official proxies are required by OTW policy to display a banner at the top of the page stating you are not on the official site. Avoid Login on Unofficial Sites
If the paper is a guide on how to use the site, it might be discussing how to manage drafts and previews before they go live [1]. Most Likely Intent: Technical/Preservation Context
(often used to bypass specific regional blocks) archive.transformativeworks.org
or other extensions are community-run and should be used with the understanding that they are not official FanFiction | AO3 unofficial - App Store - Apple
A (or mirror site) is an exact copy of a website hosted on a different server or domain. If the main site (archiveofourown.org) goes offline due to traffic spikes, DDoS attacks, or server maintenance, a mirror site allows users to read content, post works, or browse tags on a backup server.
An AO3 "mirror link" typically refers to an alternative URL used to access the when the main site is blocked or running slowly. These mirrors are identical versions of the site hosted on different domains to help users bypass firewalls (like those in school, work, or specific countries). đź”— Official & Safe Mirror Links
Most mirrors do not sync in real-time. If you find a mirror, it might be days or weeks behind. You might find a story that is updated on the real AO3 but frozen on the mirror.