The Internet Archive has launched on Friday a Chrome extension that will detect "Page not found" and other web errors and replace them with a copy from its Wayback Machine, if available. The extension is already available on the Chrome Web Store.

According to the Internet archive staff, the Chrome extension can detect server error codes such as error codes 404, 408, 410, 451, 500, 502, 503, 504, 509, 520, 521, 523, 524, 525, and 526.

Once an error is detected, the extension will prompt the user to replace the error page with the latest copy from its database.

The Wayback Machine Chrome extension in action

The Internet Archive staff, who recently announced they were moving servers to Canada because of the Trump presidency, say this Chrome extension will help fight "link rot."

The organization describes link rot as a phenomenon on the Internet were previously working links turn into 404 errors, mostly because websites go down, or they change their URL architecture or domain altogether, breaking previous links.

For example, the Internet Archive staff says that 49% of the URLs referenced in U.S. Supreme Court decisions are now dead, mostly because the websites of the US government have shifted around, merged, or discontinued.

The idea behind this Chrome extension isn't new. In August 2016, Mozilla engineers started working on a similar feature, called No More 404s, part of the Test Pilot program, that would also replace 404 links with copies from the Wayback Machine.

No More 404s Firefox add-on

In February 2016, the Internet Archive also set up a Malware Museum that showcased how older viruses affected PCs.