Do we know that the archive was deleted or merely taken offline? The blog post says "excluded" which to me imply that they still have the data, it's just not publicly available.

I hang around in emulation circles and there's been some talk in the past few weeks because some Nintendo ROM archives had been taken offline from archive.org but people soon figured out that they could still access them by tinkering with the URL. The situation is a bit different here though.