Did something happen to archive.debian.org in the last 24 hours?

Hi mirrors team,

Apologies if this is not the correct team to contact. If it's not,
please do let me know who I should be asking…

In the last 24 hours some customer machines that I support that run
squeeze and lenny¹ (!) started failing to do apt update getting a
"403 Forbidden" error from archive.debian.org.

Taking a look, http://archive.debian.org/ looks pretty empty having
only a /debian-amd64 directory.

Is this intentional? The README file and relevant wiki page still
suggest that archive.debian.org should hold packages all the way
back to bo.

Cheers,
Andy

¹ Yes I am aware that these ancient systems are in dire need of
  being upgraded. Those who own them have not given permission for
  that.