Strange! Doesn't seem to be down, at least at time of writing (either my original post or this one)

I linked the plain HTTP version... which seems to rely on a series of redirects; potentially TOR:

    ~ $ curl -vLsq http://archive.today/U5Tah |& grep -Ei 'location:|title'
    < Location: https://archive.today/U5Tah
    < onion-location: http://archiveiya74codqgiixo33q62qlrqtkgmcitqx5u2oeqnmn5bpcbiyd.onion/U5Tah
    < location: https://archive.ph/U5Tah
    <title>archive.ph</title>

Tough to say :) Vaguely reminiscent of SNI troubles on the web server... which can depend on the client. I thought that was becoming exceedingly irrelevant, though.