My home server is old enough that none of the methods
installation-birthday uses to determine its creation date are even close
to accurate.  I installed it in 1999, but:

  I: Installation date: 2004-06-08

At various points I've recreated all of its filesystems, and it was
installed before d-i existed so /var/log/installer doesn't exist.

I believe if you just added /etc/hostname to the list of files you
check, then that would be sufficient.  That should be quite widely
applicable; I think it's pretty reliably created during installation
rather than copied from images that were created beforehand.

Thanks,

We believe that the bug you reported is fixed in the latest version of
installation-birthday, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1090764@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Chris Lamb <lamby@debian.org> (supplier of updated installation-birthday package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 31 Dec 2024 14:59:32 +0000
Source: installation-birthday
Architecture: source
Version: 20
Distribution: unstable
Urgency: medium
Maintainer: Chris Lamb <lamby@debian.org>
Changed-By: Chris Lamb <lamby@debian.org>
Closes: 1090764
Changes:
 installation-birthday (20) unstable; urgency=medium
 .
   * Add /etc/hostname to the list of candidate filename timestamps. Thanks to
     Colin Watson (cjwatson) for the suggestion. (Closes: #1090764)
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