Error 404 Wayback Machine detects error codes 404, 408, 410, 451, 500, 502, 503, 504, 509, 520, 521, 523, 524, 525, and 526 and checks to see if archived versions of the URLs requested are available. If they are, a message will be displayed offering the opportunity to view the archived version.
To test this try going to: https://www.whitehouse.gov/the-record/climate

Install

• License: Mozilla Public License 2.0
• Weekly downloads: 6
• Average daily users: 245
• Rating: 4/5 of 9 ratings
• Created: 2017-01-22 15:16:16
• Last updated: 2017-02-19 22:50:22
• Homepage: https://archive.org/
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/error-404-wayback-machine/
• API: error404waybackmachine@lafleur.com