So far it's alright, and it does what it says on the tin. However, it is probably too eager to prompt the user to check the 404 page. On many occasions where the page did load, its modal window pops in my face asking me to check out any archived versions.

Worse still, the popup is a modal window that blocks out the rest of the page and cannot actually be exited out of without reloading the whole page.

Personally, I think it would be fine if there was no pop-up at all. Simply have the user access the toolbar button.

Seems to overreact with resource loading errors within the page.

This is not really properly tested.

it seems overzealous, maybe an error loading some part of the page triggers the extension to assume the entire page is unreachable? that's my guess- I'm not sure exactly what is triggering the false positives exactly. has worked a few times as intended/expected, too

Too eager! Every time it's come up, I got the desired page by clicking the link again. It's never provided a backup page that was needed.

Very useful, but buggy. Keeps trying to wayback sites that actually load and work.

Really buggy since a year ago. Shows the notice e.g. when simply navigation back and forth as others have mentioned.