* persistent systemd journal, which might have some privacy issues
(`rm -rf /var/log/journal` to disable, see [journald.conf(5)](https://manpages.debian.org/bullseye/systemd/journald.conf.5.en.html))
* last release to support non-merged /usr
* security archive changed to `deb https://deb.debian.org/debian-security bullseye-security main contrib` (covered by script above)
* security archive changed to `deb
https://deb.debian.org/debian-security bullseye-security main
contrib` (covered by script above, also requires a change in
unattended-upgrades)
*[password hashes have changed](https://www.debian.org/releases/bullseye/amd64/release-notes/ch-information.en.html#pam-default-password) to [yescrypt](https://www.openwall.com/yescrypt/)(recognizable
from its `$y$` prefix), a major change from the previous default,
SHA-512 (recognizable from its `$6$` prefix), see also
