mystery device

[Clarence Wilkerson <openbsd_(_at_)_hopf_(_dot_)_math_(_dot_)_purdue_(_dot_)_edu>]

When reading the security mail mail to root on my Sparc IPX running
current openbsd, there are a reference to /var/backups being a file
instead of a directory.

When I looked, I found

root_(_at_)_hipx> ls -lagd /var/backups
br-sr-srwx  1 976188787  1915708009   99, 115 Jul 12 19:21 /var/backups


It seemed to be unremovable, renamable, etc.
I used to have netbsd 1.2 on this disk, so it may be a remnant
from those days.

What is it?
Clarence