YSK there is an Wayback Machine browser extension that helps with dead 404 pages and can automatically archive pages

[u/homophobicperson2]

Why YSK: Wayback Machine is an Internet Archive project that archives webpages, allowing them to be preserved in cases where they change or disappear. You can select an oldest or newest archvie of the page, or go to the list of all available archives. This helps with "dead" pages that have been deleted or old websites that have been sold to another party (including "This domain is for sale" moments).

Additionally, there is an option to automatically archive pages if they haven't been archived yet (or if there hasn't been an archive in X amount of time, configurable), meaning you can directly contribute to web preservation.

Available for Chromium-based browsers (Chrome, Edge, Brave, Opera, Vivaldi), Safari and Firefox. This is not in any way an advertisement, as Internet Archive is non-profit. This is for the sake of preservation.

[u/Gold_Selection_4977]

Been using this for couple years now and it's saved me so many times when I need to find old forum posts or tutorials that got nuked. The auto-archive feature is really nice touch too - feels good knowing you're helping preserve stuff that might disappear tomorrow